Where Can I Get a Good Set of Cast Iron Cookware?

I'm looking to buy someone a set of good cookware. Hopefully, I'll have them to gift in time for Christmas. My kitchen consists of a pot, pan, and a rice cooker (probably all from Big Lots or something), so I'm in over my head here.

In talking to people IRL, I've been told Amazon is not a good place for a quality set - which I believe based on mixed reviews of my recent purchases and my own lack of knowledge on what makes a good set. I was also told to search antique stores and consignment shops for pieces. So, I'm doing that without much luck as, again, I'm just out of my depth and it's possible it will take much longer to find enough pieces to make a complete set (between 5 and 9-ish).

Does anyone have recommendations for what I should look for in a good pot/pan? Or, what are some solid brands that someone who loves to cook would be proud to own?

I'm not sure what is a good budget. Is anywhere between 500 and 1000 USD a good start?

Thanks for any advice you can give.