Your budget is pretty decent if you are only considering to purchase a mod only. If you are considering Temp Control as an option, you can look for Sigelei 150W Temp Control, IPV3-Li 165W, IPV4S or perhaps the Snow Wolf 200W (price range around $65 - $115). All the mentioned mods does not come with batteries. Therefore, you may need to set aside budget for batteries and a decent charger. If you are intending for a lower budget, you can consider the new iStick TC 40W or IPV D2 75W which is priced from $30 to $60.
Of course, the above mentioned are all temperature controlled mods. For normal regulated mods, you can consider Sigelei 150W or the iStick 100W which is priced from $35 to $70. With the budget range you have, you can get a decent normal regulated mod easily.
As I personally do not use mech mod, I will leave it to the mech mod experts to provide some recommendations.