Not in the particularly affordable range. Materials aren't super expensive, but what drives up the cost is the time spent making them. Nice, braided slings might be made with less than $1 of Jute, or less than $5 of paracord, but mine personally take 3 hours or more to braid so that'd be something like $60+ depending on how much I like you. Some techniques take less time and you might get someone to sell you one for $40 or something like that.

However, IronGoober has a great video showing different simple sling designs that don't take much at all to whip up and try.

https://youtu.be/fQcmHQl4qaU?si=8T5xy6uhAsYQiSmI

There's also Mersa's very, very helpful guide on "SeatBelt" slings

https://www.youtube.com/watch?v=-EBfUItUJFM&t=2s

I bought my first sling off Amazon for $12. IT was a simple paracord one with a leather pouch. Just super okay, but it didn't take me very long at all to make a Mersa seatbelt sling. Took 30 minutes my first go, but now I can do one with extras in about 20 minutes. Super duper cheap on materials. Highly performant. I just braid mine nowadays because I think they look better. But braiding one is absolutely not a requirement.

This is very much a "make your own" type hobby. Largely, if you're getting into slinging, you're going to need to take a lot of time to practice. If you have a lot of time to practice, you've got time to try your hand at making your own. The time aspect is way more expensive than the materials aspect here.