You can grab a Zmax 15w for $9.99 right now haha, it's an older mod (15w is pretty low wattage, although vapes GREAT with a 1ohm to 1.5ohm coil, in my opinion) Uhmmm, no, really- What is it you are willing to spend? A regulated tube mod? Hmmmm... What-about the Itaste from Sigelei? Again, an older mod with lower wattage limit, but vapes great for my personal vaping needs.
If you had/have 70 bucks, I would recommend the Provari or Provari mini. You can get the 2.5, I believe, for right-around $75 right now. AGAIN, a semi-older tech mod, but the highest quality regulated tube mod that you will EVER have the chance to purchase (they are made in the US & they are unstoppable. do a search for Provari here on ECF and you will quickly see that they have quite the following. They were and still-are considered the most durable regulated-mod ever made. I could-not recommend them enough.
As-for box-mods, I would highly suggest either the EvicMini Ego-ONE tank, or of course, the Kanger SuboxMini w/ Subtank. BOTH of these mods are basically the most-popular mods in their class. I own both & I can promise-you that they pack a punch & the build-quality is VERY sturdy & trustworthy. The Evicmini hits 75w, the Suboxmini will hit 60w, and both mods will provide you w/years of vaping, if you take care of them. Trust me when I tell you they are quality made mods. Single 18650 (I recommend you grab at-least 2 18650s, but it would be great to have 4 on-hand) mods... The EvicMini's screen is gorgeous, huge, bright, and clear! The SuboxMini's screen is compact, blue background, bright white lettering. Both screens are just-great! Both mods have relatively good batt-life, although, I must-say, the SuboxMini's battery-life continues to surprise me regularly... It lasts a good long while! I promise! For single batt mods, if you aren't vaping at ULTRA high wattage, they'll give ya 20-30hrs constant vape-time depending-on the mAH of the batteries you wind-up purchasing. (the 1st two numbers in the mAh rating, tend-to allude-to how long they will last (constant vape-use wise) IE: a 3000mAh battery should give you around 25-30hrs constant vape-time. A 2500mAh batt should give you right around 20-25 constant vape time hours.

(very rough estimations) SO, these mods will last ya, batt-wise. So-long as your not vaping at 60w haha.
I can also recommend the SnowWolfs, the KooporMinis, the Sigelei MiniBook, the Sigelei150w, ugh, all of these are pretty good choices. (these companies are doing their best to carve their path out-of the market and make a proud and popular name for themselves, in the regulated-mod market) competition is fierce, and mod-quality is up. Always google for reviews of ANY mod you are about to purchase. Come here, to ECF, and search the mod's name, ASK US if it-is a good mod, etc/etc....
I hope I've helped you in some-way and I hope you're able to choose a good mod soon

Have a great day/night and 1 more thing real quick- ENJOY the vape journey, my friend.

Have a good 1.