If money is tight you can run race meets without transponders and still have pretty accurate results.
Most of the RC race management software designed to be used with transponders can be used manually without transponders.
So you need to put numbers on the cars and have a spotter person call the car numbers out loud as they pass the line and another person pressing the numbers on the computer. The race software does the rest and so you can produce professional race results.
So you only need a computer, race software which is free and some pre-printed self adhesive numbers.
I ran many race meets like this many years ago.
There is a list of RC race software on this page
http://www.transponderservices.com/F...-services.html
and go to the section titled "RC model car race management software"
Ultimately you need a Mylaps RC4 transponder system. They are expensive but very reliable and used world wide as the RC standard.