YOU can get steve jobs round rimless glasses less than $50 from some online optical shops. Search round rimless glasses online, you can find many online glasses shops offer such eyeglasses. As far as i know, Firmoo.com provide round rimless glasses that steve jobs worn in a very low prices. I see some round rimless eyeglasses at firmoo.com ranges from $19 to $30. So, go ahead for a pair of cheap round rimless glasses there.
Shop around at the vintage stores in your local place, you may find steve jobs round rimless glasses by chance. Glasses in the vintage stores are very cheap. Or you just search them online, you will find round rimless glasses that are similar to the style of steve jobs eyeglasses. You can get them with low price from framesdirect.com. They have a large selection of steve jobs for you to choose. However, in my opinion, they are a little expensive. Good luck!