Alas, just back from a week in Son Parc about an hour ago!
Anyhow, with regard to food shopping, we found prices high on most items. I had kept some receipts to share prices on here, but the wife has just told me that she dumped them before we left the villa this morning!

... Very useful! ... However, from memory, and shopping mainly from the big, newer supermarket in the Poligon Industrial Estate near the Airport in Mahon, we paid (prices in euros)...
MILK... 1 litre of local ... 1.55 (Imported Cravendale was 2.50)
LOAF OF BREAD ... Anywhere between 1.80 and 2.50
LONG FRENCH STICK ... 0.90 to 1.20
4 PACK OF ICED DONUTS ... 2.90
MARGARINE (500g) ... 1.80 for local up to 3.00 for imported (Flora)
MATEUS ROSE WINE ...3.80 (4.80/5.25 in Son Parc supermercados)
TOILET TISSUE (6 pack) ... 1.84 for decent stuff (0.85 for bog standard (excuse the pun) 4 pack in Son Parc)
HELLMAN'S MAYONNAISE (medium sized jar) ... 2.40
STEAKS (4 thin cuts for BBQ) ... 5.00
CHICKEN KEBABS (4 for BBQ) ... 4.80
BEEFBURGERS (4 pack, locally wrapped) ... 3.80
FISH (dorada) 3.40/4.00 each
CHEESE SLICES (8 pack) ... around 2.00
HAM SLICES (8 pack) ... around 2.00
SAN MIGUEL BEER (small can) ... 0.70, (large can) ... 0.95, 1 litre bottle ... 1.25 - 1.80
ALL FRUIT AND VEG ... reasonably priced and comparable to UK.
As we were in a villa, we choose to BBQ a few times, but we ate out at the Pinomar (I think it was called) in Son Parc, where we had 4 routine main courses, a small bottle of water, 2 cokes and a small beer ... cost was 49 euros.
Last night, we decided to go to eat in Fornells and stumbled upon a veritable gem of a restaurant called El Pescador. We had 2 rounds of garlic bread and 2 starters ... Prawn Cocktail (I know)

and a delicious spinach and prawns in a creamy sauce!
4 main courses ... roast chicken and a wondrous roast pork shank for the 2 kids, pork in a stoganoff sauce for the wife and a mouthwatering sole stuffed with prawn and salmon in a heavenly sauce for me! (all with accompanying veg/chips)
Then we had 3 desserts (approx 6.00 each) ... chocolate crepes and profiteroles for the boys, and a chocolate sundae ice cream for me!
2 cokes, a bottle of water and a small beer ... total 80.24 euros ... a real bargain! I'm so sorry that I waited until the last night to go there, otherwise it would have been a regular haunt!
Was in Cala'n Bosch yesterday lunchtime and bought 2 kebabs for the kids (which weren't great, TBH) for 5.95 each!
Crikey! ... what a long post!
Hope this helps a bit!