Willisbrow, welcome to the world of being a rafter. There's a bunch of good info here and I see a couple of things here I want to call out for new rafters. Sure, some folks may find exceptions to these "rules" but in general, what's below is very important to being a raft owner, so to sum up what's been said above and add to the discussion:
1) NEVER rely on any kind of electric blower to completely inflate a raft. These are usually designed for getting most of the air into the raft, and most will burn out if you try to completely top off the raft with them. That's one of the reasons we have hand or foot-pumps - to top off the raft after the electric inflator has blown it up as much as it can. When you air up a raft, you'll hear a change in the pitch of the blower noise - that means its no longer pushing air though but is just spinning the turbines while the motor overheats. Finish it off with the manual pump.
2) There's a big difference between a compressor and a raft inflator. A compressor is a low-volume, high pressure device, a raft inflator is for high-volume, low pressure. If your buddy wants to blow up the raft for you, have him turn his shop vac to "blow," make sure its not blowing out sawdust or junk, and air up the raft with that. Then be ready to top it off with a manual pump when you get it on the water.
3) Any time you're heading to the river, you should have a manual pump along with you. There are several reasons for this: A) if you ever need to do an on-river repair, you'll be up the creek with a flat boat without a pump. B) Temperature differences - its pretty common, especially in early spring, for the river temperature to be much cooler than the air temp. When you put the boat on the water its likely to get really squishy unless you top it off after its had a chance for the air temp in the tubes and floor to equilibrate. Also, if there are big temperature swings where you're going, if you beach the boat on a hot afternoon, you may want to let some air out, then top off in the morning when its still cool. I've also heard of rafts popping when driven from a cool morning garage into a hot desert afternoon.C) Altitude differences - if you're driving over mountain passes, you may need to let a little air out before you head up, and reinflate at the bottom. For example, in driving from Denver over the continental divide, the altitude difference will result in an additional 2 psi in the tubes, most boats are designed to run at about 2.5 psi - if you're topped off leaving town, you could either pop your boat or really stress the material and seams.
Ture's right about the noise but I most folks will recommend using a blower for airing up the raft and a manual pump to top it off. If you're going on the cheap, a Bravo foot pump works great (~$35). I've found them very durable compared to the small cheap hand pumps you can get at sporting goods stores or even raft shops. Whatever you do, get a manual pump even if you're trailering your boat already inflated.
Have fun on the river,
Nothing in the world is more yielding and gentle than water. Yet it has no equal for conquering the resistant and tough. The flexible can overcome the unbending; the soft can overcome the hard. - Lao Tse