As a general rule, the better the phone the higher the price. And, like a computer, how much power you need depends on what you are wanting to do. For gaming you will likely want a higher end phone, for just checking email and surfing the web, you don't need as much phone. There is also the problem, with Android, of what version it comes with -- unfortunately most phone manufacturers don't create the drivers needed to update their phones to newer versions of Android. This is part of the reason so many here like rooting and custom ROMS, putting user created versions of Android on your phone that don't come with the "pre-installed software" that the carriers install, have more options, and often offer updates to newer versions of Android.
As a minimum, currently, I'd likely want at least a 1 Ghz processor (top of the line is a 1.5 Ghz dual or quad core), 512GB Memory (top typically is 2GB currently), 1GB storage at a minimum (high end is at least 16GB) -- this does not include microSD card storage, more on that in a bit.
Most high end phones are currently shipping with screens 4" or larger; how large you want your screen is a matter of personal preference. Some prefer larger screens to make things easier to see, others prefer a smaller screen so that the phone fits more easily into a pocket and/or in their hand. Also, there is the screen resolution, most high end phones have a vertical resolution of 1024 or higher.
As for storage, the reason for having at least 2 GB is so that you have room for Apps. While you can "move" apps to the SD card, at least part of the app has to stay in main storage. At the same time, Android also takes up a few hundred MB of storage -- so the less memory you have, the less apps you can fit on the phone. Also, some apps must stay in main storage and others don't support being moved to an SD card.
As for apps, most apps you will likely buy from the
Google Play Store. Unlike Apple, you can load apps from other locations. One example is the
Amazon Appstore for Android. As with PCs, you need to be aware that you get your apps from trusted sources and may wish to be aware of what permissions apps want; for example, some apps will want access to your contacts or phone log despite not having a need for that information. At the same time, many apps want access to your phone status, this is largely so they can pause if you get a phone call.
The last issue, is data and data speeds. One major complaint about Virgin Mobile is their data speeds, though that depends a lot on where you live. For example, I switched from Virgin to T-Mobile because I was typically getting download speeds of 300 Kbps or slower -- and in some areas could do no better than dial up speeds (under 100 Kbps). Virgin does offer WiMax that has download speeds up to about 10 Mbps, but that requires buying the Evo V and is only available in larger cities (you can see the VM coverage maps to see where it is available). All Android phones can also connect to WiFi, which has the advantage of not counting against your data limit and is typically faster.
There tend to be two types of "data limits". First is where you have a set amount of data you can download -- after which you have to buy more data or are just completely cut off. This is fairly rare anymore; most mobile companies instead provide "unlimited" data, though they throttle after a set amount; throttling meaning they slow down your data speeds. For Virgin Mobile, you get your first 2GB each month at full speed, after which they throttle. The exception, again, is with the Evo V -- Virgin is not throttling people who have the Evo V, which is 4G (WiMax) capable.
As I mentioned before, Virgin Mobile has been quite slow in some areas. You can get some idea of it from PC Mag's report on the
Fastest Mobile Networks (just select a city on the right side), though that information is now about 6 months old. Of particular interest is the far right column, that shows the percentage of downloads they did that were greater than 144 Kbps. For example, looking at Houston you will see that only 45% of their download speeds were faster than 144 Kbps, while every other provider (other than Metro, which isn't in Houston) was roughly 98% or higher -- that really highlights just how slow VM has been in Houston.
I'd recommend talking to friends who use Sprint/Virgin Mobile/Boost in your area and see what kind of data speeds they are getting. If Virgin Mobile has decent speeds in your area (1 Mbps or better) then great. OTOH, if Virgin is slow in your area you will likely find yourself frustrated, just like if your home Internet is running slowly. And, unfortunately, which carrier is best for you depends on what city you live in and, sometimes, even what neighborhood you live in and the areas you frequent.
