diy Draping: Buy fabric, curtains, or rent?

It depends on the drape length you're looking for. White cotton or silk blend fabric is fairly cheap, and will come in varying widths to get the look you're going for.
If you want to practice how it will look and get an idea for how much curtain/expensive fabric you may need, muslin fabric is very cheap and will give a good estimate of length needed!

I'd shop around a bit, you can find really cheap sheers at places like Burlington Coat factory. I sew so I buy fabric a lot and you can find some really good sales sometimes but fabric can still get very costly. Look around and see if you have a discount fabric place near you, I have a place near me called Affordable Fabric where all the fabric is 2.99 a yard but they don't always have a good selection. Joann fabric is always having sales so check often to see if they have the fabric you want on sale, and check online for coupons, there is always some sort of coupon online for Joann Fabrics.

Shop around, see what's out there. My Mother found satin for $1 a yard. I currently have over 10 yards left and I'm nearly done with all my drapery. I will say that sewing them has been a pain. My most recent was a backdrop for the head table over 15 feet long. Buying a bolt will be less expensive than buying by yard. Shop around, look at online stores that aren't popular, normally they have wonderful deals.

Ikea currently has really long sheer curtains that are beautiful for $5/panel. I believe they are 96" long. I was going to buy them for my arch, but one of my BM's said she already has some sheer curtains that I can use. If there isn't an Ikea in your area, I'm sure you can order them online.

Hi https://ShipOur.Wedding rents just the draping (search 25' short drapery swags). They're 37.50 per panel of fabric & come in 10+ colors. This is available in the menu under Ceiling Drapery. You can figure out how many panels you need after you check the date in the black box. There are also other pipe and drape diy backdrops available at super affordable prices. Congrats 🎉

Renting is almost always more economical. You have to figure your time/labor at minimum wage on top of the price of supplies when DIY which ends up being more expensive..and most do not need the fabric afterwards. Unless you plan to reuse it, you won't get back what you spent.

Thrift store, ikea, Ross, home goods
Basically start looking around and stock up. Keep all your receipts just in case your vision doesn't come together but it usually does. I typically go on my lunch break 1 day per week and try to find cheap things for our wedding

EBay has a lot of affordable sheer window drapes that work great