As and when time allows I'll add more detail about my own thoughts on each of these things but for now - here's a summary of the equipment you'll want and a rough buying order (there's always going to be some variation from person to person and some things are equally important so it's a judgement call)...
- Mask
- Gloves
- Jacket/Gambeson
- Synthetic Waster(s) (and Buckler if you're doing I.33)
At this point you've matched and exceeded the school loan equipment and are covered for controlled synthetic sparring. - Gorget/Throat Protection
- Cup
Particularly important for men which is why it places highly on my list though there are both male and female versions available. - Overlay/Back of Head Protector
- Leg Protection (shins/knees)
- Arm Protection (forearms/elbows)
At this point, depending on the quality/level of your equipment, you may have suitable protection for controlled steel sparring. - Upper Leg Protection (fencing trousers/skirt)
- Chest Protector (optional but recommended)
- Weapons, Bucklers, Shields, etc.
These should be the last thing but they're also the most exciting thing so probably won't be.