How can I do my own 3 inch lift on 97 tacoma without buying a lift kit?

Suspension is a poor place to cut corners. When it breaks you crash.

You will either spend a couple hundred dollars on a lift kit from a website like Toytec, or spend a few hundred dollars on some billet aluminum, spacer design, and machining. And since you are asking here, it is clear that you do not have access to the latter. Your heart is in the right place but I think another gift might be a better idea... for example, does he already have a nice floor jack and jackstands? Doing basic maintenance with him is cheaper than a lift kit, plus you both learn in the process.

if its merely suspension raise spacers like revtek sure you ought to use the inventory stuff those 3" lifts ar upload ons on your modern suspension. if its a physique raise kit you dont adjust the suspension

Without a lift kit?

You can't.