If you go to a head shop and buy a pen, they usually sell some cheapo ones that cost like 25 bucks. Those will last you maybe 2-3 months before you need to get a new one. I would look online for some pens or get one of the more expensive pens at whatever shop you are at.
Generally if you are getting a vape for weed, most pens will come with a coil/double coil that heats up and glows orange. These will need to be replaced maybe once a month but they generally arent very much to replace. Maybe 10 bucks a pop. These coils are good for every type of concentrate (oil/Wax/Shatter). If you are looking to get a vape for dry herb, it will take a different type of attachment and pen.
There are some pens you can look into that range from 100-150 bucks that come with 4 different heads for different types of weed (dry/wax/shatter/etc.)
Personally i just get the cheapo vape pens from headshops because I never want to spend 100+ bucks on it. I've gone through 4 of them already though. You gotta be careful with them too, they can break easily and sometimes the metal pads that connect the coil to the battery will break and your coil wont heat up or charge.
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I bought the $100 one, but I've never needed another. You'll end up paying the 100 one way or the other.