it dawned on me last night after i had signed off that you can pick up a team associated apex mini/rc18 off ebay for good prices. iv seen rollers go for as low as $40. i was bidding on one a few months ago with a radio and servo, no motor or ESC. it sold for $50 somethin. and those are pretty good cars.
or you can always go this route.
http://www3.towerhobbies.com/cgi-bin/WTS1000p?&C=C there's a short course truck 9th down that says box damage only, $85. or the DT first on the list, says works fine and it's $84.
i recently bought 2 of the dromida's off there cause they were so damn cheap. complete RTR package, battery and charger included, even came with batteries for the radio. there not bad, wont win any races or set any speed records but for just running around out in the street they work pretty good. they even have hop ups available
http://www.dromida.com/surface/hopups/index.html
or hell do a little research on the ECX you wanted to know about in your original post. maybe that'll actually work for you.