we are staying at shoal bay east (manderaim beach club). How close is a grocery store?

If you make a left on the newly paved road down near SHoal Bay and continue on to Island Harbor there are several small stores-For a full service market go up the hill (main Road) make a left at the large intersection, then stay to your right where the road forks-Vendor booths there in the trees on your right) continue on this heading south and at the round-about go right (heading toward the valley) you will get to Best Buy which is a full service market with fresh produce, meat etc. You are also near TRopical which is a great source for liquor, wine. soda, snacks etc.

How are the prices for food & alcohol in the grocery stores?

Food is a little high; great prices on alcohol at Lake's in the Valley. Tropical Flower usually has the best prices on water, wine & booze but we have stocked up at Gifts & Liquors on the main road just west of the Sandy ground roundabout -- good prices & a nice selection.

You'll want to keep in mind that in many of the stores, the marked price is in EC, not US dollars. At first my wife and I thought that the prices were unbelievably high (15 dollars for a 4-pack of small water?!?). And then we figured out that most items were in EC!

We found good goods at pretty good prices at Proctors in the Valley. Lakes is good, too.

FYI - US currencey is accepted all over the island but official currency is the Eastern Caribbean dollar. Here are a couple of tips when dealing in EC money. First, the exchange rate you get will vary - officially it's $2.6882EC=$1US but you'll get anywhere between $2.65 and $2.70 to $1US. If possible, try to keep your transactions in the same currency, i.e. if you pay in $US ask for $US in change. If you pay in $EC get $EC back in change. This will not always work because vendors have a habit of giving you change in the opposite currency so the get a "little extra" in thier pocket because they will do a "double" conversion.

Bring a small "credit card size" calculator with you to help with conversions so you'll know the price you pay for items. Some vendors mark both $EC and $US prices on their merchandise. If you see only one price it's probably $EC (except in resort gift shops which usually mark prices in $US). If you are not sure if the price shown is in $US or $EC ask, then make your decision to purchase or not if you think price is fair. Finally, if you don't have a calculator handy you can use this simple formula - divide $EC price by 3 and add 10% - the result will bring you fairly close to the $US equivalent. Happy shopping!