Steve:

I am not an expert if this field by any means but the Official US Casino Chip Price Guide list the Grubstake from 300 to 750 and the Main Street 101 from 150 to 300. Of course the book is several years old now and may be completely out of date. Personally I think 30 to 50 would closer to the actual value of these chips at this time. But keep in mind I am no expert. Good Luck.