ROTARY VS COIL

there is actually a DVD and a book your can purchase at http://www.tattoobooksonline.com :3
as far as rotary VS coil I personally prefer coils as you can alter, and customize them to suit you
your problem is probably crappy chinese machines
buying off of ebay is really never a good idea

if money is not an option then i recommend this kit
http://www.tattoomachineequipment.com/the-hildbrandt-professional-tattoo-kit-system

or this one
http://www.tattoomachineequipment.com/the-hildbrandt-starter-tattoo-kit-system

if not try this one out
http://www.tattoomachineequipment.com/tattoo-kit-inkstar-ace-machine

i recommend the first link if you can afford it. the first one comes with AMAZING machines that will last you your entire career.

then when you need more supplies you can pick this one up
http://www.tattoomachineequipment.com/tattoo-kit-refill-pack

if you email them they will even let you pick your 50 needles/grips to suit you as not everyone uses the needles in this kit. i always customize this refill kit to fit my needs
http://www.tattoomachineequipment.com/tattoo-kit-refill-pack

you can even check around that site for other things like just machines, medical supplies, etc.

id say start off with the DVD, and Book from http://www.tattoobooksonline.com, and make sure your machines are tuned properly, and you are doing things the right way. always feel free to ask questions around the forum. we’re always here to help!

Best thing to do is to become a tattoo apprentice. And practice on things other than people! Basic Fundamentals of Modern Tattoo will help you out though.

oh im happy to ear those machines are good…cause i did order 2 one linner and a shader :)