Welcome to ECF!
Rather than throw a suggestion at you, I'm just going to give a few things to consider about some of the suggestions here.
The MVP V2 seems to be the most highly suggested. A lot of people here on ECF swear by them so it can't possibly be a bad product. THAT BEING SAID... I do not own one. I own several vv/vw mods, but there's two things about them that I should bring up vs the MVP.
First off, none of my mods are box mods. Comfort in the hand is more important than you may realize, so I can't personally vouch for how a box mod feels to use. I'd suggest watching a few reviews, such as from PBusardo on YouTube, I believe he's reviewed the MVP and the VTR. Watch how it's held during use and ask yourself whether or not you'd like it. Just my two cents there.
Second, what keeps me (personal opinions and preferences here, people, don't be offended) from even trying an MVP is that you have to plug it in to charge. What are you to do while it's charging?
All if my mods use 18650 batteries and I have a LOT of them. So when the battery gets low, I simply slap it on the charger and put a fresh battery in my mod so I don't go a minute without being able to vape.
Someone recommended the VAMO. Don't be too quick to discard this device. Decent quality, made sturdy, offers vv/vw, and (actually can use 18350s) as well as 18650s. At least my VAMO 2 offers that. I use it as a backup so I haven't looked into the newer models. But it's a quality product that runs roughly $50-$60.
Those are just my thoughts. If the MVP looks comfortable and you don't mind it having to charge a few hours then definitely give it a shot. If you'd prefer something you're fairly certain is comfortable and that you can swap out batteries in, then you might want to look into vv/vw mods in your price range that follow that criteria.