errrr.... they sell etching kits where I live... (Chicago area) admittably crappy ones, but they've still got ferric chloride in them.
I think it depends on the store, but it seems the they are generally doing away with electronic parts and supplies and focusing on consumer gear and cell phones.
Main problem with this is keeping all the traces in circuit, or they wont etch. You could cut a small part of each trace first, leaving a bit that wont need etching, then put a big blob of solder over the top to complete the circuit. The solder blob will take a lot longer to be removed , but should probably put some etch resist over it (since it will be sticking out further, and have lower resistance). This can be a lot faster than ferric chloride, just use a 12v computer psu. For the negative? electrode, use a sheet of metal close to the pcb, to minimise resistance, but make sure it cant possibly short, use a multimeter to see current and move it closer untill it gets near the max of the psu (10-20A?) There will be chlorine gas so if your going to, do it outside on a windy day. I tryed this once on a big lump of copper, but had the supply mied up and ended up with a nice textured piece of aluminum.
For the amount of stuffing around that you've got to do with this method, and the limitations that you have, i.e. that you can really only do trivially simple designs, you're heaps better off using a toner transfer method and a conventional etching process. I can go from EAGLE layout to finished PCB - for a moderately complex single sided PCB - inside an hour, half of which is drilling the holes.
Look for Ammonium Persulfate, rather than Ferric Chloride. Or try a decent serious electronics supplier, rather than Radio Shack.
another good etchant: 1/3 30% HCl + 2/3 3% H2O2 clear when there isnt too much copper in it, can be easily regenerated
