Ok well others might have more accurate amounts but things like basic food in supermarket is not that much cheaper than home , some like netto & hiperdino, are dearer than others. If you're just looking for basics It's not much of an issue anyway. Large 5 or 8 litre drums of water are a little over a €uro or so.
Drink varies, you'll have plenty happy hours in bars on the strip with large local beers for under €2 but you can pay €3.50 for the same in some restaurants. Meals out can be as cheap or dear as your budget allows. There are 3 courses for under a tenner or you can pay €40-50 a head if you want. The choice is huge and generally, the quality is all good. If you were planning on driving, car hire can be got for around €50 for 2 days with main hirer like Cabrera medina, some others may be cheaper. Buses to the other towns are very reasonable and frequent. Lots of sports and music bars, too many to mention individually to be honest.
Try and get out to see the island, you can do tours on bus with last minute travel who have several offices on the strip and there is another one I just can't remember the name that do same. If you want to go to the Sunday Market in Teguise the buses are about €6 return, the reception in apartments will probably have info on it.
Either way, you'll enjoy it. The weather is looking good for next week and there are very few places to beat lanzarote, ( except maybe Fuerteventura

)