It's as expensive as you want it to be (a familiar concept to those of us with UAS). I got a 10" Fire tablet for $100 on Black Friday. Plus a $30 case that works as a tabletop stand. MobileSheets Pro costs $13. The built-in Kindle software reads PDFs and I've added a variety of apps like GuitarTapp, none of which cost more than a take-out order of pad thai.
That's $143 and change. I could get by without the case and I used the free version of MobileSheets for years, so really it's 100 bucks. How much do you spend on paper and ink to print things out?
The Fire fits in the pocket of my concert uke case. I can set it on a table or balance it on my lap so I don't need a music stand. I don't need a clip-on light, either. The Fire weighs a bit more than the 2-sided printout of the local uke club's weekly 28-page song packet. And I have
all the song packets.
YMMV. I'm happy with a cheap tablet because I use it for reading and email and web browsing. If I wanted to edit photos or run real-time performance software like GarageBand then I would need better hardware. If I played from tab or standard notation (mostly I use chord/lyrics sheets) then I would prefer a bigger screen. My son plays piano and uses a 10" Lenovo tablet for sheet music and fakebooks. His eyes are young.
I've never felt the need for a page turner. Most songsheets fit on one page if you do it right. When I do need to turn a page, at worst I'll miss one strum to tap the screen, which is no problem at uke club.
If I performed solo,
and didn't work from memory,
and used music that requires page turns,
and couldn't reformat that music to put the page turns in a more convenient spot in the music,
then I would consider getting a pedal.
Like so many other things, using a tablet requires an up-front investment of money and time, so you can save money and time later. If you've ever grumbled about lugging around a 3-ring binder full of music, I think a tablet is likely to be a good investment for you.