She also may already know it, but you being a novice horse owner don't know how to do it yet. No offense intended, I have just been following your threads and know that your new to horses and all... so she may know it and just need to be brushed up on it.
However, she isn't too old to learn if she doesn't already know it somewhere in her background.
Horses have only ever been sold for cash or check in my experience, when paid by check usually the horse can't leave the property until the check has cleared. My family has bought a few 5-digit price tagged horses, and sold some too. It's really more of a show thing though, price doesn't always reflect how well trained they are or anything. Bloodlines and show performance go into the price a lot. So, for a family pony I am SURE, in this economy especially, you will find something between 1k - 5k easily... horses cost a lot to maintain, so people are trying to get rid of them faster right now.
Also, random but, I'm happy you're getting another horsey eventually- Molly is probably a little lonely :)
Proud owner of 13yr old Paint Gelding, Bali! <3