If you are going with a new truck and want to do crawl on the more serious side, expect to spend $600.00 or so on a crawler. Otherwise search the used market i.e. Ebay, forum classified sections, etc.

If you go new, the best way to start is with a Tamiya TXT-1. It's an excellent crawler out of the box. Then add a radio (a cheap one will work, but you will need at least one very strong servo for the front). Add a Novak Super Rooster ESC and a battery and you are in business.

TXT-1 ($360.00)
JR XR2i Radio ($90.00)
Novak Super Rooster ($125.00)
Cheap batteries (3 @ 10.00 a pack = $30.00)
1/4 scale steering servo ($60.00)
Motors (2 silver cans come with it, but if you are crawling replace those with two Integy 55 turn lathe motors at $20.00 a piece)

Total = $660.00

If you already have a radio you can save $100 or so off of the above listed price and if you have batteries you can save a little more. The Novak Super Rooster is the only way to go with a crawling ESC. It can power two motors (wired in series or parrallel) and gives 3 amps of receiver power (to power the big servos). Better to buy it at the start than spend money now and upgrade again later.

If you look at the used market you can usually pick up a TXT or Clodbuster for around $200 - $250 but they may need work or may need to be set up for crawling.

Even on the used market you will spend close to $500.00 when you add electronics.

If you want to go on the small side you can go with the Tamiya TLT-1 (1/18th scale truck), but it needs some work out of the box to be able to really crawl at any level. With a lot of work, it can become a very nice crawler.

Here is a pic of my TLT that is now just a bit short of 1/8th scale.