Weekday lunch rec near Chicago Botanical Garden
Charlie Beinlich's is close by (on Skokie Boulevard I believe). Old school bar with great burgers (but limited menu).
Right ner Beinlich's is great Italian at Hole in the Wall (may be pushing your dollar limit though).
Also on the same street is Barnaby's for great thin crust pizza.
Some of these places may get crowded around lunchtime. And there are a number of other restaurants up and down this street from Dundee to around Lake Cook Road.