regulators should be changed every 5 years I think (might be 10, can't remember, don't have a set anymore). hoses should be free from defect (impossible to proof on Ebay) and replaced every 5 years, flashbacks should be changed more regularly. torches are fine second hand assuming they can be proven safe (valves etc. can be changed out easy enough and nozzles are consumable). a trolley is a must if you plan to move it around, that can be second hand or build your own. the BCGA website is worth a look for real information on it, I know you aren't a business but the advice given should still be followed.
Unlike acetylene, propane is fairly easy to bottle and doesn't leach in the same way, compressed oxygen on the other hand scares the **** out of me (having seen what it can do first hand) and a flashback is going to leave a nice stain on the back of your pants. second hand kit seems like a bad idea to me where it's concerned. Seek guidance from a professional before you touch it (best bit of advice never to follow I know), you might change your mind.
it should be noted that oxy propane is a shed load safer than oxy acetylene and with the right knowledge can be a really useful tool to have at your disposal, talk with your local supplier to see what safety precautions they suggest and decide from there if it's benefits outweigh the costs.