I like the Apraise brand of tints, they are inexpensive, the darkest (blue) black is really intense for lashes and the Browns are nice - I use light brown a lot with a dash of grey added. Apraise is sold by a number of wholesalers including Aston Fincher who have a 20% discount event this weekend.
Rosie is right about needing to try waxes before you stock up, there are loads of different products. You need to shop around for consumables like spatulas and paper strips. Bulk buying is worth looking into, typically buying upwards of 40 packets of paper strips (50 if you prefer thinner strips) is discounted as that's one large box full and buying 50 packets of 100 spatulas can save you as much as 50p a packet, because that's also a full large box and it's easier to pick, pack and dispatch full boxes of stock. However never buy loads of something you haven't trend before as you might hate it!
There's lots to think about with heaters, so you might want to buy an inexpensive heater to start with, to get some practise and then find out what factors are important to you. I like sleek heaters without a handle, but I've had one slip out of my fingers and drop its hot contents all over the floor - a handle would avoid that hazard. Also wax pot size is another consideration, are you going to decant wax into an inner pot or do you want to use wax straight from its pot so you can keep your heater clean and swop products easily? If you're buying wax to use straight from pots you need the right size heater. And finally do you want double pot wax heater or a single heater. Double size heaters don't fit on top of the standard wax trolley, so you need either a more expensive waxing trolley or an open front equipment trolley without an annoying lip that gets in the way of the heater flex.
If you are close to London there is a big trade show at the end of March called Professional Beauty. It's a great opportunity to see lots of products in the flesh and take advantage of show offers. There are usually online deals available around the same dates, so make sure you sign up for lots of wholesalers newsletters.
I buy my wax equipment and products from Essential Beauty, who have their own brand Outback Organics and also supply other brands. They are not the cheapest, but they do know their wax and equipment and I've been very pleased with the advice they've given me about which products to buy. Their own brand of heaters are slightly better than the other brands in my experience - although I love my sleek hive digital heater and EB stock hive equipment as well.