what year XJ are you running? I ask since the newer (97+) XJs don't handle 3+ lifts without transfer case lowering kits or SYE+ new driveshaft. A 3"+ lift may require more than what comes with those lifts you mentioned. If money is an issue then I would suggest saving a little longer and get everything you need all at once. Or go to a junk yard and build your own rear leafs, some ZJ coils, and then spend the rest of your money on the other things you may need.
The list of things you may need (every XJ is different):
Longer brake lines (front and rear)
SYE (either H&T or full replacement of the output shaft)
New Driveshaft (either junkyard solution or custom ordered)
Bumpstops
New Control Arms (adjustable is the best way to go)
Quick Disconnets (your anti-sway bar links will be too short reguardless)
An adjustable Track-bar (or drill a new hole OR leave it alone and have the axle off-center)
An alignment after your lift is done is required!
I'm sure I left some things out so a search should find what you may need.
I had to save for about 2 years before I had enough info (THANKS
!) and money to do it right the first time. This way I spend my time wheeling and not trying to fix things as my patch solutions break.
Whatever you decide to do, you will enjoy it (working on it and wheeling it). Good luck and ENJOY!
JMHO,
Rough
To answer your question: I always order online/phone since it is way cheaper than going into a brick/motar store and buying from them.