Many reasonably priced tanks about, and it is true that the Toptank mini is pretty diverse. I don't own one with that said, but those who do seem to really like them.
If you want something inexpensive (and may take a little time to get there but it's a nice way "into" building, would be something like a Joytech Ego One Mega V2, can usually find one cheaply. You do have to get the correct coil, the Joytech CLR coil which will come in 1.0 or 0.5 resistance. They are kanthal coils but pretty easy to rewick and rebuild and many folks will rebuild the coil with stainless steel wire at whatever chosen resistance and have used it in TC mode. The coils last, but they are also really surprisingly easy to rebuild.... You'd have some time vaping in wattage mode unless you want to rebuild a new coil, but I tend to find that is better to "Learn" to vape and your preferences in wattage mode will likely help you as you are getting oriented.
If you want to jump in at the deep end, if you are more MTL I'd suggest a Siren V2, and/or an Ares, both RTAs, good capacity and flavor, and they offer a great vape. The berserker is a nice MTL vape but the draw is extremely restricted, which may not be what you want. I'd also metion the doggy style clone can be found at Fasttech for very inexpensively. People tend to love or hate that tank, but it gets great flavor and lots of folks swear by it. You don't want the authentic (unless you want to pay a ton) but it is seen as a good option as far as clones. The Kayfun clones are decent, it's really not something I've had a lot of success with but a lot of folks are swearing by the prime, and the Kayfun lot tend to buy original but it is so expensive, it would be out of your price range, I'd suspect.
Having a hard time coming up with great options for drop in coils, and if you are looking for sub0hm I'm not your girl although I'd put in a vote for an Engine (although I hear they are being discontinued) single coil build deck, people love them. For a drop in tank, probably the Original Crown if you can find one. The crown 3 gets good reviews but it's not as versatile in coil type as the original Crown.
Best of luck,
Anna