Here's some recent sales on three word domains with store or shop. Looking at these sales most seem to require the third word as part of the meaning (e.g. hiphop) with the exception of "PremiumWineShop". However "PremiumWineShop" is 15 char's long while "HealthyGroceryStore(s)" is 20/21 char's. These are, however, strong keywords.
Domain TLD SalePrice SaleDate SaleThru Len Wrds Num
HipHopStore com $2,788 Jun 05 Afternic 11 3 N N
PalmDesertShopping com $2,400 Jan 06 SnapNames 18 3 N N
DigitalTVShop com $1,000 Mar 06 Afternic 13 3 N N
BritishCornerShop com $750 May 06 Sedo 17 3 N N
PremiumWineShop com $630 Feb 06 eBay 15 3 N N
Cheers,
BidNo