Cheap as chips

Not Spain, but we went to Malta last year and everything was very cheap there.

My friend goes abroad a lot and uses Travelzoo. We booked with them once about 6 years ago and had a good value hotel break in Cornwall.

EasyJet do holidays and quite often have flash sales. If you fly midweek on EasyJet or Ryanair the fares are cheaper, you could book somewhere on Airbnb or even stay in a mobile home.

We always look at Jet2 and Thomas Cook last minute deals, We have snaffled a few bargains in our time.

Some of the packages are very cheap just after Easter when the school holidays are over. Also some flights are cheaper on specific days and times during the week.
Taking only hand luggage can drastically reduce the cost.

Travelzoo (Europe edition)

There are lots of Spanish package holidays, makes it easier. Have you looked at Jet2, I've booked them on line a few times and they've have been good, no problems. Good luck, I'm sure you'll have more chances to go again!