I had been doing a lot of research on kayaks before I bought a used Mariner Propel recently.
One suggestion I would offer is to allocate a significant amount of cash for accessories, too.
Paddle, PFD, paddle leash, whistle, anchor and rope are mandatories. I would highly recommend an Onyx inflatable PFD from Academy ($80) or you'll have a thick layer of foam getting between you and the seat back.
If you're going to fish at night, you'll need a 360 light. I think mine cost $20 from Walmart. According to YouTube and Google, you can also make your own for cheaper.
I don't know how you're planning on transporting your kayak, but I bought Yakima bars cushioned wraps for the top of my car. And you'll need straps and tie downs. Those were the second largest investment behind the boat itself. Obviously ignore if you have a pickup.
Then there are the optional accessories that you really should have for an enjoyable experience: rod holder(s), crate, anchor trolley, kayak cart, waterproof case for your phone/wallet.
When I was renting kayaks from a local place, I "borrowed" a crate from a nearby restaurant and zip tied a piece of PVC for a rod holder. And I made my own trolley using $20 worth of hardware and rope. But again... these things still cost some amount of money.
I'm not saying you can't have a good setup for a few hundred bucks, but you might have to adjust your expectations to match. Good luck.