I've been doing a lot of research on getting a new mod as well. I started out with a Roughstack, which I like, it vapes really, really well on 18650s at 3.7v and it works with stacked 123cr's, but I am not fond of stacking batteries especially if they are not protected and the unit is not regulated. I also hate the button on the roughstack. It has one of those hard little buttons and after vaping on it for a while it hurts my thumb and leaves a dent.
After looking at all the mods, I decided for the next one I wanted a variable voltage, because that offers the most options in what can be used as far as cartos and attys, LRs and HRs. I like having choices. There are some pretty good inexpensive box mods out there, ranging from $29 to $59, some come with bottle dispensing and others don't. But I didn't want to go with a box mod. They are just bulky in the hand. So I was looking at the Provari and Lava Tube. I like the look of the Provari, but can't really justify spending over $100 on a mod right now. So the Lava Tube was my next choice. The Volcano site (the home of the brand name of Lava Tube) has them for $99 for a kit, but the kit only includes a Trustfire charger...which I don't like because it doesn't regulate the charge of the batteries and has the possibility of over charging and blowing up. (I'm quite concerned with that happening.) So getting the kit from them then buying a xtar or pilla charger would be an extra expense.
After searching for several days, I realized all the vendors that carry "lava tube" style mods are all carrying the exact same thing gotten from companies in China. Now going through the companies in China and only ordering one or two of these units costs $35 a mod plus $29 shipping, and it does come with a full kit, but the batteries and charger are crap so it really doesn't matter. But it's going to end up being about $65 from china, but then you also have Customs to worry about.
I found a site that I just posted a question to the board about as a vendor, but it's Elite Vaporworks. They have a good set for $74 on sale right now, xtar charger and AW batteries. It's a really good deal, and I am hoping they are an in country company, but I have emailed them to ask, as the don't list their place of business on the site. I haven't ordered it yet, but I'm pretty settled that I probably will order from them unless others have had a bad experience with them.
So box mods will be the cheapest way to go, but not by a whole lot. Roughstacks are cheap but the button sucks. Smoketech Bolt style mods are also under $45 each, but they are only 3.7v. All the other mods are pretty much over $50, many closer to $100...and they all basically do the same thing 3.7v, and the just look different.
To get the best deal it's really a matter of looking through a gazillion sites and figuring out who has the best deals going on when you go to order. Sometimes there are sales, some sites have coupon codes, and others are just priced less all the time, so it's just a matter of hours and hours of research and googling and comparing prices and products and features.