What do you mean safe?
Any of the established firms are fine.
I have only used Bright, and they will give you your money within a day if you need it. I think they have scaled back in the last few years, but still have a dozen or two offices. There are many other firms as well, depending where you live.
I'd recommend finding a "prop" shop near you that you like, and then inquiring here. Be sure to ask about desk fees, etc.
jay