Generally speaking, small kites - below 150cm - tend to mass produced in cheap materials designed for families to use in the park or on the beach. Usually cheap ripstop sails, fibreglass rods and stretchy nylon lines and the frames tend to be very flexible.
More serious stunt/sport kites are generally around 200-250cm with much better quality ripstop or polyester/Icarex sails, better stiffer carbon fibre frames and much better fittings, contruction and design. A bigger kite with a stiffer frame and well designed sail will let the kite in lower winds and with more precision than a cheap flexi kite. A bigger kite also tends to fly more slowly so you have better control and can see what is happening and have time to react to that.
You don't have to spend a fortune to get started ( you'll probably do that later!...be warned!) as you can get a new ready to fly set up that will fly well, let you start getting into tricks with decent dyneema lines for around £80- £110ish. Once you have the kite costs are minimal - wind is free!!
As a first kite look for a good 'standard' kite around 2-2.5 m with carbon frame and a Dyneema lineset as this should let you fly between around 5-18 mph winds which is ideal for a beginner. Once the bug has bitten you'll soon be adding more specialist kites to your kite bag.
Ask lots of questions before you buy, you'll get plenty of answers here.
If you want a copy of a very good kite flying E book PM me your email address and I'll send you a copy.
Current Bag:- HQ Shadow, Spiderkites Zodarion, Flying Wings Soul, Old blue HQ Jive , 'PAW' modded HQ Maestro II, Delta Hawk,