>>12V Walmart (or insert generic department store name here) pump:
>>Does pump the tire, but: 
>>
>>	Taking my four "small" LT195-75-R14 from 20 to 45 psi takes
>>	40 minutes!!! (including "cool down" intervals for the pump
>>	to keep it from smooking.) 
>>
>>	After 1 year of use (only maybe 10 or so of these cycles,
>>	plus occational topping off) the pump performance seems to
>>	have degraded significantly.
>>
>>The pump I'm talking about is the "250" psi 12v one. It comes in
>>a dozen different outsides (with and without: pressure gauge, extra 
>>12 V outlet, various color lights etc), but with the same pump inside. 
>>Prices range from $9.95 to 39.95. Surprisingly I havent found any
> alternative
>>to this pump. Any 12v "candidate" I've examined, regardless of brand name
>>contains the same pump inside the varuious shape housings.

For what it's worth, I bought one at Kmart about 1-1/2 yrs ago for roughly 
$17.00.  There were two there, a few bucks apart.  The one I bought was the 
sturdier looking of the two, brand name Interdynamics, 200 psi. (The 
cheaper one was labeled 250 psi, but just looked flimsier so I passed on 
it.)  I've used it many, many times since then.  A little slow (maybe 15 
minutes from flat to full, definately not 40 minutes!), but has proven 
extremely reliable.  Gets a little hot to the touch after prolonged use, 
but has never overheated or failed.  It's helped me out of a bind many, 
many times - best $17 I ever spent!  I keep it in my Vanagon at all times. 
If my experience with reliability is typical, I'd recommend this one.
-Ron Salmon