The worth of Adderall and Ritalin

My friend wants to know this:

How much is a 30mg time release Adderall XR pill worth
vs.
How much is a 30mg time release Ritalin pill worth.

I've seen kids sell it for 2 bucks a pill, but what would be the lowest/ highest price to pay.

Thanks

i pay about 2 bucks for a time release...sometimes just $1

2 bucks / pill time release for me

2 dolla