Any company I have worked for will let you use a set of spare climbing gear to start out. If you're good they will buy you new. I always preferred to use my own climbing gear (once I acquired it) and so have all of the other experienced climbers I have worked with.
I keep an extra saddle, rope and gaffs for any new prospects that come along. I also like to have the extra gear in case a rescue situation should arise.
Check your local pawn shops. It's not often that you will find climbing gear there as most climbers tend to hang on to the stuff that wins their bread but sometimes you will find some decent stuff there. If you find gear there it will usually run you about a third of the regular price. I found a set of like new aluminum Bashlin gaffs in the pawn shop for $75. With the pads and straps, they would have gone for over $400 new. Break out your yellow page book and start calling ahead that way you don't waste a trip.
I would recommend getting a new climb line and lanyard though.