We have a lot - with extensions (will take a few, but can't take them all because of space). We've had them for a while, but they are still going strong. Some of them have started to age (colour into an off-white, but still sturdy). But we have them as is and think they look fine (or look up Billy Ikea hacks online :-)).
 
To buy, message saying:
- How many and which combination you would like (eg "one skinny and one thick)
- When you could come pick up in Maplewood NJ
- Name your price
 
Need books to fill them up? We have tons of books too :-) (can't list them all, come have a look!)
 
Thank you!
 
More info, dimensions, pictures and 360 from ikea:
https://www.ikea.com/us/en/catalog/products/S89217751/#/S59182201
https://www.ikea.com/us/en/catalog/products/50263838/