Just to throw in my two cents to the "LARPing is expensive" problem...
As far as costuming goes, I found a handful of different shirt, vest, and skirt options at thrift stores which I can mix and match. They cost me about $15 total for 6 pieces of clothing. And that required no sewing at all.
Shoes are harder, but I'm convinced I can either find an old pair laying around or put something over my sneakers to make them work or buy a pair for under $15.
I also got leather-looking vinyl and suede lace from JoAnn's for about $20 total. I cut it into a vest, put the vest together by punching holes in it and lacing it up with the suede lace, and I have plenty of material left for other things--arm bracers, leg bracers, a helmet, shoe covers, you name it. Again, none of that required sewing. Just my time and energy.
The stuff I made might not last more than a handful of events, but I think it's totally fine for someone who's trying Alliance for the first time and doesn't want to look out of place.
I think the MOST expensive thing is the cost. I believe you have to buy yearly membership for each chapter you want to play in, or just buy it for the weekends you attend. And if you want to PC it's $65 for each event. Even just playing in one chapter for the whole year will be about $300.
A good idea is to NPC. You have to pay the yearly membership, but the events are free. Something to consider if you want to play but you're on a tight budget. Then all you need are black pants and a black shirt.
Pc or NPC, you're gonna need a sleeping bag, pillow, changes of clothes, toiletries, bug spray, a battery powered light, snacks, and transportation.
And I almost forgot about a boffer weapon! You can make one for relatively cheap. Maybe under $10?
Gosh, listing all this is making my wallet cry.
But honestly, a lot of the more expensive stuff is only one-time purchase stuff, or stuff you won't need to re-buy often.
If you tried, you could probably NPC one chapter for under $100-$150 a year. That's less than $20 a month, which is really cheap by any standards.