If you want something cheap and easy to get started with, look into the Motonica P8C 2wd or P8F 4wd. The 2wd car costs under $600 with engine, header, and pipe. The 4wd costs about $25 more. You don't need expensive servos and the car is very easy to build. It uses an adjustable off road style clutch and the clutch shoes last forever. You hardly ever need to adjust or maintain the clutch. Long term operating/racing cost is about 10% of what you would normally spend on a 'normal' on road 1/8th car. There is not much to break or wrench on, so you spend more time driving and less time in the pits. There is no 2 speed to mess with and you don't really need an expensive setup jig or even a tire truer (for the 2wd at least). Tires last a long time, especially fronts. You will get at least 8 minutes a tank, so your fuel expense is also reduced. The only major drawback is the car is not as fast, but it does teach you how to drive smoother.
A large number of parts are shared with the P81 series cars, so if you later decide to move up, you can share parts with your new car. You can see the cars here: