Mech mods, as others have stated, come with their own array of safety procedures that should be followed 100% of the time and if you haven't done any reading yet on the stickies on this forum for battery and general mod/rda safety then please do so before purchasing. Mech mods are very simple (metal tube, 2 contacts) but they have no protection unlike VV/VW devices.
Battery safety is the main concern with mech mods as we use unprotected batteries. If you are considering rebuildables (which you will get the most bang for your buck vape quality wise if you go rda/rba/rta+mech or just a tank with a rebuilt head. Vaping on something like a vivi nova and a mech is just fine but you might not get the most ideal vape...anyyyyyyyywho if you are considering rebuildables look into getting something simple to start with (youde's igo line is a great starter place, I love my igo W and igo L) also the smoktech octopus is a fantastic cheap rda(I HIGHLY recommend drilling an extra air hole for better airflow as the stock airflow is trash) and will give you a great vape.
Head over to the few mech mod threads we have going on the APV section and read up! You can get a mech for pretty cheap (30-70 bucks). I recommend the Hcigar 1:1(meaning close to the authentic original version) clones. I have 2 sitting infront of me; the copper and gold ring style nemesis. They are fantastic mods and I picked up the both up from my local vape shop: 49 for the gold ring and 60 for the copper. You can get these cheaper online, but nothing beats going to a brick and mortar and getting a hands on experience with it and being able to talk to someone who has, hopefully, a good bit of knowledge on vaping.
Best of luck!