I agree with previous poster with regard to rental income. There is lots of competition on the costas for rental. Also familiarise yourself with tenancy laws in spain. Short term rental is ok but longterm rentals can be tricky – 11 month max longterm lets are the norm any longer term and the tenant has rights. The law tends to favour tenants rather than landlord in spain. I know that in a good location, upmarket urbanisation the rental income on a 2 bed apartment you would get apprx E450 per month. The maintenace fees vary but expect to pay on costa blanca anything up to 450 per year. Suma E150. One piece of advice if buying don’t just go for cheap because it is cheap, take into account location, amenities, closeness to airport and watch out for what neighbours might be like!
Good luck in your decision! 🙂