I have a number of hydroponic gardens. Some smaller, and some larger. All of mine are AeroGarden units:
https://www.aerogarden.com/ -- no affiliation, just a happy customer.
Most of them, I purchased new from the manufacturer. Although I do keep my eye on CraigsList and OfferUp and have found some real steals that way too.
For me, I like the convenience of the units. I like their guarantees too. Mostly, I buy my own seeds (+ sponges, pods, etc). Right now, I have two flower gardens going in my kitchen. I love flowers in the kitchen! I have one herb garden still growing, although I just ended a lot of them. Life is a bit of a distraction right now. I also ended 2 huge Jalapeno plants, but I have two small Pot-O-Penos beginning to give fruit. I have 2 Golden Harvest Cherry tomato plants going. They are a less acidic kind of tomato that DH can handle. I just ended my lettuce garden too, but I have 4 huge bags of lettuce in the fridge. I plan to start a new lettuce garden soon (takes 3-4 weeks to start producing a good deal of lettuce for me.) And I'll plant a new selection of herbs too. Nothing like having all the fresh herbs just a few steps from the kitchen.
So, it depends upon what you want to grow and how much work you are willing to put into it. From many friends, I know that the DIY/homemade gardens don't save any money and can be tricky to get set up and going.
If anyone wants to know more about the gardens I have, just ask.
Tomatoes
Pot-o-Peno
Herbs
Lettuce