If you really want to get in cheap, find an artillery unit. All you'll need is your uniform. They didn't wear sidearms while working the guns. Any unit will have some loaner gear. If you're interested in the infantry, look for a used musket. New ones are extremely expensive right now. Several sutlers like Fall Creek have a basic uniform and leather equipment package that will set you up for any mainstream reenacting experience, and honestly some history heavy ones if your attitude is good. By the time that uniform wears out, in 3-5 years, you'll know if you want to keep reenacting, and can replace your worn items at your leisure, upgrading if you want and are in a place financially to do so. You can also look for used gear here and on other fora. Generally, buying used will get you higher quality at lower price than the item cost originally, and you can avoid the "look at me. I'm a brand new reenactor" look.