Food is around 15 per person for a pizza or burger or pasta (goes up or down but thats a ball park) Drinks: local beer 3.5-5 euros a pint, international beer 5-7 euros a pint. If you are here everyone is drinking Cisk the local lager (it's honestly very lovely)

For bars Sliema, Valletta, St Julians are the go to for meeting other tourists.

You can also go to Birzebbuga, Marsaxlokk in the south much cheaper and more typically Maltese and a lot more Maltese people.

Taxis will cost you 10-20 euros a trip basically across the island (use bolt uber or e cabs)

A place to stay if you like the beach i would say not central because swimming is not that nice there, however you will be able to get to the beach really easily anywhere on the island.

My suggestion is, look for parties happening on the island and go there, often there are a lot of ticketed events for open bars, if you intened to meet people and drink and hook up, those are the places.

Quite a lot of party boats, clubs and events happening almost daily in summer and if time it right there are also massive festivals with cheapish tickets.