I trained with i-lash designer systems in 2006, and still use them now! They have a HUGE range of sizes, widths etc, as well as specialist lashes like the mink, y, w and coloured lashes. The customer service is fantastic. I still email before and after pics to them for feedback if I have tried something new etc. I cannot fault them!
Another popular company in my area is xtreme lashes. My advice would def be to avoid the "wholesaler" brands and training. I have had to use one of these brands in a salon I worked in and they were awful!
Another idea is google lash extensions and you will get most of the companies. You can then have a good old nosey around the sites and get a feel for them. hth and good luck!
Oh ps, you will LOVE doing the lashes, its a great treatment!