Proper Temp Thermostats

[Piggybuns]

Hi there, as some of you know, I'm new to the snake-game. Ghost, my one and only lil corn snake baby is doing really good so far, she likes to explore and hide under multiple hides now instead of just her plastic plant, which is good. I moved her into a smaller tub for now rather than the whole 20 gallon and she seems to enjoy the more enclosed space. (Till she gets bigger of course.)

When I got her, I got a Reptihabitat 20long Snake Starter Kit With Tank, which came with a LOT of useful things to kick me off the ground for. But the little thermometer they gave me is this cheap plastic little round thing that I know for a fact is inadequate, the only thing I didn't really care for when I got it. I'd already researched corn snakes for 10 months before buying, so I double checked everything before I got it to be sure the substrate they gave me was right, the size was right, and the tank has a track-lid, so no pushing out kinda deal. It's actually pretty nice, except for that.

I want one of the digital ones with probes you can stick in multiple places to determine temperatures and establish a real good heating gradient, and just got my check. I'm expecting it to be pricy, so I'm not concerned about price right now, I'll do what I gotta do to keep her warm and comfortable! But uh, I'm completely new to this or how they work, or where they go in the tank. Or even how to work them, though I'm guessing the book will tell me.

So you guys have a lot of experience and most of you have multiple snakes. What's a good one to get? I don't know any companies in order to determine reliability, and I want to be sure what I get is good and not cheap like the sad little plastic one they gave me for now. (It was just a starter kit, I kinda knew I'd have to replace some things with nicer stuff which I plan to do here on Monday! I'm so excited to spoil her with all kinds of things. But important stuff comes first.) So far, the temp seems to be right, and the undertank heater is comfortable enough with substrate on top for her to sit and burrow under, but like I said I have no GOOD accurate way to determine what her temps are right now.

So... best ones to get? Ones to avoid? Added accessories to keep things regulated? I heard there was something that could change how a heating pad heats up (it controls it? I dunno maybe I heard that wrong.)