MBK's business is instructing, having fun with kites (not sure "having fun" is a business) and developing kiteboats (that's a loss making "business"!). We are not retailers.
We used Griffin kites for many years and still occasionally use them. Give Chris at Griffin a call or email if you're interested in that Australian brand. We've been using Switch kites and Shinn boards for a few years and find them excellent. Switch is an online only brand - with corresonding low pricing. We've found the product to be of very high quality.
For students first trying to get up on a board, a very large board with a small relatively underpowered kite is better than a bigger kite and large board. The Spleene Door64 which I use for teaching is 164cm x 46cm, has soft rails and planes with much less power than most boards. This is a substantial advantage when first learning. The chance of a scary over powered experience is much less with the lower power/big board combination. Many a kiter in the southern end of Moreton Bay has had his/her first ride on the Door!
As a new kiteboarder you will not want to use the Spleene Door for very long. However, neither will you be able to progress to your final optimum board without a lot of heartache and frustration. If you can get a big volume, soft railed light wind board to practise on, you will progress much more quickly, and with more safety, than otherwise.
Having gained competence and confidence with a light wind board, students should consider something that they will ride when riding independently in higher winds. There are many preferences for board characteristics...you'll have to discuss this with me and other riders and try boards from those providing demos if possible.
The Griffin twin tip board (137 x 41 or 133 x 39) is an excellent entry level board. I use one most of the time (OK...I have lot of other toys like race boards, directionals, iSUPs, light wind twin tips etc...but when I use a regular twin tip, the Griiffin is great!).
Apart from a kite and board, you'll need, depending on your preferences, a harness, booties, PFD, helmet, sunglasses, etc. Harnesses, PFDs and helmets are provided by MBK for lessons. You'll need your own booties (depending on the site being used), sunglasses, board shorts/rashie etc.
Harnesses are generally classified as either seat or waist. I recommend and use seat harnesses for teaching. I also use a seat harness myself but many prefer waist harnesses. You should try several before deciding what you want to use.
PFDs and helmets are a matter of personal preference. Very few kiters use them - that puts me in the minority. For flat water kiting, I can't see a disadvantage in wearing a PFD. Although I recall it being annoying when I first wore one, I now don't notice it being on. Having it on is quite handy when you just want to have a rest in the water - and I'm sure it helped when I broke a rib on a very bad landing from a very high jump. Similarly with helmets, you get used to them quickly - and they keep a bit of warmth in winter!
There is an awful lot of used kite gear on the market. There is also a lot of awful used kite gear on the market! One of the two biggest mistakes the budget beginning kiter will make is to purchase cheap and very inappropriate used kit. (The other big mistake aimed at saving money would be to not have lessons!)
Kites and safety systems have progressed very quickly over the last few years - this should not be surprising as kiteboarding is quite a young sport. Many of the earlier kites are very poor, particularly for beginners, in comparison to modern rigs.
There are some modern very good pre-loved kites available and there are some shockers. Moreover, even some of the good models may be in very poor condition. I can't give general advice on kite gear on this web site. But I'd strongly advise you to get some advice before purchasing any used gear. It would be much better to fly a trainer kite and have an initial lesson before thinking about buying any gear. You might want to consider buying a power kite after that. Give me a call if you want to discuss options.
You might want to consider my thoughts on practice before thinking too much about getting gear.
Don't expect to be able to get a safe and satisfying rig for a few hundred bucks....
Some indicative prices for a reasonable rig might be the following (with used prices for reasonable kit in parentheses):
Kite: $1,300 to $2,200. ($700)
Board: $800 to $1,200. ($500)
Harness: $150 to $300 ($100)
Sunglasses: $15 to $150
Lost income (because you go kiting instead of working): Possibly heaps.
So budget for around $2,300 to $3,500 for new kit and don't expect to get any change out of $1,300 for used gear - even that would be a little skinny. Some retailers of course offer packages...These might include low level gear or gear they can't otherwise move but also might be good value. You might also be lucky and pick up a full used rig at a good price from someone on Seabreeze .... Also you could get pre-loved boards and kites quite a bit cheaper....but the chance of the kite being safe and depowerable (easier to learn with) and the board being any good for a beginner would be low.