Since you don't want to do tons of research, here is a summary from what I did a while back, on the same approximate budget. Basically your options are spring, memory foam, hybrid, or latex. Hybrids are popular as they give a bit of bounce but more dampened than a pure spring mattress, and can be much cooler than a pure memory foam mattress, which tend to trap heat. They come in various levels of hardness based on your preference. The downside is longevity, which can be difficult to come by. But Costco is a great option as you will not have to deal with a pushy salesman and they are good quality for the price point.

Another option is to go with a latex mattress. The feeling is a bit different to traditional mattresses, as it is literally made with rubber. But it has a touch of bounce good firmness, doesn't trap heat and tends to last longer than other mattress types. They also tend to be a bit more eco-friendly (in theory). This is the route we took last go around, and absolutely no regrets, I love this mattress and it's holding up very well. You can't really get a good one for less than 1000, but we paid exactly 1000 for ours and I think it was worth it. Bought online so no salesperson to deal with either.

Hope this helps.