I think most people who visit Varadero go there with a package that includes airfare (likely from Canada) and 4 to 7 to 10 nights' lodging. It works out pretty reasonably that way because the Canadian tour operator can buy blocks of rooms in bulk and resell them. Almost nobody does what you’re planning on doing. You’ll be quoted the one-night rack rate at one of the resorts and it won’t be a good deal.

A much more basic place is Hotel Los Delfines. It's right in town but has a beach. It's showing its age. If you're not too fussy, it might do the trick.

www.islazul.cu/es/hotel/hotel-los-delfines

The webpage shows prices from €68.70. That'll be per person and the most basic low-season rate, all inclusive.

Islazul is one of the state hotel chains. Any Melia lodging in Cuba is also state owned, but the government has turned management of those lodgings over to the Spanish chain.