I think the most popular budget priced vv/VW devices out are the Vamo, Zmax, eVic and the itaste. Watch the reviews on youtube to compare and decide what you like. The are all under $100 and good devices. The all have their pros and cons though.
Vamo is $50 or below. Fairly big and heavy. Powerful workhorse with a good build quality. Can't use some devices like the T3.
Itaste SVD is just under $100. Very long device. Great quality. Very easy to use.
EVic is about $105. Smallest of these listed. So so build quality. Works great but try not to drop it. Very technical menu and features. Tech heads love it. Firmware updates and lots of neat toys.
Zmax is just under $100. Smaller than the Vamo and itaste. Great build quality. Again, can't use the T3 and a few others. Tons of options and settings. This is my preference out of these.
There are two companies that make the z-maz. Smoktech and sigelei. They are very similar. The sigelei is slightly bigger. There are reviews for both on PBusardos page.
Watch youtube channel PBusardo for the best reviews on all these devices. He may not have a review for the iTaste SVD. Grimmgreen does though. Hope this helps.
you can buy a 510 to ego adaptor for 2-3 dollars and that allows the T3 to be used on vamo or any other mods