If you love the tone that you can get from an amp then you will enjoy playing the guitar at its fullest. If you get a cheapy amp that can do what you want it to, then you'll probably never want to touch the guitar again.
The first question is tone. Do you want a more classic tone from your guitar amp, or a more modernized digital sound? This is an especially important question if
you plan to do a lot of playing with distortion. However, even if you plan to play with just strict clean settings, you also need to determine what kind of tone you will be able to get from an amp.
In my own personal experience I have found that I can get the exact tone that I want out of any amp. This is because I have a mental amp that guides me when I am tweaking the knobs of any amp. In other words, I have over the years created the perfect settings for a guitar amp in my mind, and this is true of a lot of guitar players.
A good place to start figuring out the right choice in amp is number of speakers and speaker size. If you want a practice amp then a simple one, ten inch Rental mobil lampung speaker amp will work, but I highly recommend going with an amp that has two, twelve inch speakers. This is pretty standard and it really doesn't have to cost you that much. My reasoning is that if you are going to spend the money on a practice amp, then you might as well spend a couple hundred more to get a full amp. You'll probably end up doing this somewhere on down the road anyways.
An excellent starting amp would be the Marshall MG250 which has two, twelve inch speakers, and 50 watts of power. Fifty watts doesn't sound like much, but this little amp can put out a decent amount of sound, while at the same time maintaining a good deal of diversity in the settings, especially with its contour feature.
I have worked with a lot of guitarists who were very strict about tube versus digital amps, and I would agree with them that you can get a great tone out of a tube amp. However, these guys were using the ever infamous and expensive Mesa Boogie half stack set up. Unless you've got a few thousand to lay down or can find a dealer who carries Mesa Boogies, I don't think you need to go that far.
The truth still stands in the fact that you can get an excellent tone out of a commonly played on and standard guitar amp. The tone is really up to you and there is so much accessorizing that can be done with any amp to get the desire sound.
I said this, because if you are just buying a guitar amp for the very first time, its very important that you don't start off with a bad experience.
Stray away from generic brands, or not so commonly known amps. I don't doubt that there is such a thing as the holy grail of amps, but don't attempt to pursue that kind of amp until you've had a little bit more experience under your belt.
My favorite amps have always been Crates. I still miss the sound that I could get out of them, but they are notorious for giving out right around the two year mark. I have had three now and they all went out the window at the same time.
If you are not too prudish about a more digitally processed sound, then I also highly recommend the amps that Line 6 puts out. They have a good range of models as well as price range, and all of their amps come with excellent effect features that can accommodate clean or distorted playing. Currently, a Line 6 Spider III 75 1x12 amp will run you a mere three hundred dollars, and its a really fun amp to play with.
My advice would be to stick with any of the big names when it comes to amp makers. Fender, Marshall, Vox, and Line 6 all produce excellent guitar amps,
at the same time providing a diverse range of budget.
My final advice, which is the best that I can offer, would be the process of elimination. Go to any store and take the time to try out many different types of amps. Play around with the settings and be sure to experiment with the effect settings as well. Don't feel stupid for doing this as it is common for a guitarist or bassist to walk in and try out the gear.
Buying an amp, especially your first one, can be a big deal, and any employee of a Samash or Guitar Center understands this very well.
Take your time, and just like when purchasing a guitar - don't settle.
Like any electronic product, things do go wrong at times with amps. Regular or intense usage eventually causes problems to occur, which can be sometimes fixed. So before you through your old amp out, try to find out what the problem is and the cause, then see if it can be fixed.
Problem 1: Not Turned On
It may seem silly, but often the reason why an amp is not working is because the gain level is not turned on. If the gain level is not on, no sound from the speakers will be produced.
Problem 2: Wiring
A short circuit is a common problem in all well used electrical goods. It can be usually detected by the fact that the amp jumps between on and off or completely fails. Have a look if the any of the wires appear to be broken, causing a short circuit. A preventative action is to reframe from placing wires near any sharp edges, alleviating the risk of short circuits.
Moreover, check all wires connections, from amp to speakers to stereo to car, as any one of those wires could be the source of the problem.
Problem 3: Fuses
Fuses can also be the cause of your amp not working in your car audio system. A fuse on an amp is usually located near or on the power side. Check the amp's fuse and if blown, find out a professional to replace your amp's fuse. If the fuse keeps blowing, there is clearly a major problem with your amp, which probably means you will have to replace it.
Problem 4: Over Heating
If you use your car audio system intensely, you may find your amp cuts out. Over heating in some models causes permanent damage, yet, some models (usually from Pioneer) have a function that turns off the amplifier when overheated, protecting it from damage. If you have a model with this function, simply wait till it cools down and resets itself. If you don't have this protective function, simply let it cool down and test it out again. If it works, try to use your car audio system a bit more carefully in the future and leave your amplifier in a ventilated area. It may also be worth investing in an amp with cool down functions, which regulates the amps interior temperature, making sure no damage through heat comes to the interior components.
There are other various reasons why your car audio amp many not work, which are fixable and are not. If you can't find the problem, either take it to a car audio specialist or replace your car amplifier.