In the US, an "estate sale" is when someone dies and their heirs sell all of their belongings. You would only say "I went to several estate sales" if you spent the day looking buying dead people's stuff.
If you went to look at houses to see which one you wanted to buy, you would say "I went to look at houses" or "I went to several open houses." (An "open house" is when someone who wants to sell their house gives 3-4 hours for people to come and see their house.)