There are a couple of peripherals that can be used as wireless Sheet Music page turners, but both cost around $80. YouTuber dsmp89 put together a DIY version that only cost $35 AUD (USD$36). I like the results! This looks pretty solid.
For complete technical details on how to do this yourself, check out this forum post. I spoke to dsmp89 and he had this to add:
"This Logitech K230 wireless keyboard [That he modified to make the Page Turner] can have like 2 years of battery life from alkaline batteries! That's why I went with Logitech, rather than other brands, and for $12 this keyboard was a super awesome bargain not to pass up."