I need a good shop jack

I use the jack to get it up, then immediately put jackstands under it.
Never had an issue, even on wood blocks.
As you stated, you won't be lifting the entire truck off the ground, but certainly go with a higher rated capacity jack if you feel it's necessary.

 

Ive had a Snap-on Ya700 floor jack for nearly 25 years and put it through hell and back . Fits in the back of the truck , the handle unbolts and the thing is very tough .Its a little heavier but you get what you pay for . Lift is 24 inches @ 2 1/2 tonnes . I believe Lincoln makes them . You can get parts for them and they are very reliable .
Here is a little reading http://forum.ih8mud.com/threads/ya-700-snap-on-lincoln-walker-floor-jack.384943/

 

I've been happy with the 2.5-ton floor jack I got from NAPA. I think it cost around $99. I use a 4x4 block of wood to increase the 'throw' since I'm lifted. The only thing I don't care about it, is that it touchy to let it down gently. Turning the handle to drop the vehicle back down it is rather sensitive.

 

SO how about a bottle jack over floor jack?

 

Another source for jacks is pawn shops, craiglist and newspaper ads where shops are closing, etc etc.

You can find some really fine stuff there if you are patient, have cash in hand, and know what you want. IE, if you see it, don't come back here and ask about it, because if it's good it won't last long.

That said, I have the 2.5 HF race jack, but I needed it's low profile for another vehicle. Even then, I had to drive the vehicle on ramps if I wanted to get the jack under the center of the front cross member. Then set it on stands. It held up well, with multiple jackings per month to swap race/street tires, routine services, etc.

This jack is at full extension just to do a tire swap/brake job on my Highlander or my 5 lug Tacoma. Not the best, but will do for me.

If I was getting another, I'd be getting a bigger one.

 

I've been getting by with the cumbersome under seat jack but man is it annoying. I used it to put on my spacers and I had to park just right in my uneven driveway to get the front wheels off the ground with enough clearance to remove them. I had maybe 1/2" to 1" clearance to get the tire off. I started looking at floor jacks again. The Craftsman 3.5 ton lifts to 22". The highest lift jack in stock at Harbor Freight goes to 18 1/4". I'm about to remove spacers and do a tire & wheel swap to larger tires (265/65/17 to 265/7516). It's a minor bump but I'd like to have clearance to do this on flat ground anywhere if needed. How about a Hi-lift jack? HF carries a "Farm Jack" for $55. The Hi-Lift is $75. I'd do $75 for the convenience and crossover use for other purposes. I have jack stands that go to 21 1/2".

Edit: hmm. I guess I wouldn't have clearance to the frame though, would I. Dang.