If you do not have a lathe, the best tool to get is a Willards tipping machine.
All other tools either require tremendous amounts of time to perform the task correctly, or sometimes are limited to their design and will just never get it right.
Porper makes several 'shaver' tools that if used properly work. Of course there are many other tip 'tools' for shaping tips. As for actual tip replacement without a lathe, it's pretty hard to beat the Willard Tipping Machine. I've seen one in action and they work. The only reason I've never bought one, is because they're pricey, and if you triple the cost of a new Willard, you can probably buy a fairly nice used lathe. It won't be a made for billiards/cue lathe most likely, but a lathe nonetheless.
I agree with Willards machine if a lathe is not an option. I do most all of the tips in my area and couldn't get a lathe... the Willards machine was a great investment and last a long time and parts are readily available. Takes a little practice and watch the video. Once you get the hang of it, you might have the tip replacement monopoly in your area.
Good Luck
Agreed on the Willard Classic Tipping machine. For something that's small, doesn't require electricity or steady precision hands, it's hard to beat:
https://youtube.com/watch?v=oL1OLkClBAE
The tool consists of:
1. A precision grinding wheel that flats your ferrule perfectly (and perfectly perpendicular to the shaft, too)
2. A tip holder that, after you apply glue, mates the tip with the ferrule
perfectly centered every time. It does it so precisely, that you could technically get away with using contact cement because the tool "touches" the tip to the ferrule at perfect center without having to reposition (as you would with liquid CA or other cements). Although you'd want to use CA, polyurethane, or Tweeten tip cement because they are point-purpose.
3. The tip trimmer, although technically a "pencil sharpener" as the lathe elitists will sometimes call it, does a perfect job (and even installs a bit of a bevel that will account for the tip squashing down a bit) as long as you don't go at it like you were sharpening a pencil.
4. Ryan Theewen is behind the operations in making these, and last I heard, he's in the process of making the tip shaper attachment that looks like the normal Willard shaper, but obviously the tipping machine holds it perfectly and precisely to the tip, centered. In the meantime, you could use your favorite tip shaper of choice after you use the tipping machine to install and trim the tip.
It's not a trivial expense, sure, but like someone said above, you get one of these (and especially if you keep it with you, in e.g. a small toolbox with the colletts, tip holders, assorted tips and glues, etc.), and you'll be the hero tip installer wherever you go. The machine will pay for itself in no time.
-Sean