If you get into organized racing though, you eventually start feeling pressured to have a second kit for parts, a backup engine, three-four sets of tires, etc... Hell, you can easily drop $150 just for a preheater with batteries.. - and lots of people do.. I think for what it is, 1/8 scale racing is very expensive. You can show up with an RTR Losi for ex.. But within a season you'll double your investment at least.. Not including fuel..
And that IMO is about as cheap as you can really do it.. Double the cost (minimum) of a Losi RTR not including fuel.. As an exception some may be able to pull it off cheaper, but not many will.. My opinion anyway.
I guess it's different all over. But here in Germany anyway, if you want to really get into racing, you need a mobile home/RC garage. Seriously
Each track in a given series has only a couple races a year, so you have to travel around to the different races. At every race the parking lot is always filled with mobile homes... So yeah, take that Losi RTR and multiply the price times 50 or whatever...