If you buy one of those el cheapo plastic rafts and happen to spring a leak in it, make sure you bring a good size pump along to prevent going under. You could also attempt to orient the leaking air to provide you with some forward propulsion in order to make it back.

Don't laugh, this actually happened to me once after I sprang a leak in a PVC raft and I spent more time attempting to keep the raft afloat than in paddling back! If the leak is on a seam it's not repairable, as mine was. Nothing but garbage!!!