Let's see if I can remember the prices and only counting things that are actually being used and not including consumables...
Tank,stand, lights: $1200
Sump: $120
Return pump: $160
Plumbing $50ish
2Xseio M820: $140
Sand:$20
Liverock 50KGish: $500
Topoff: $40
Skimmer, test kits:$800
Heater:$30
Thermometer:$30
Refractometer:$120
Timers, power strips etc: $150
Total: $3360
Probably another $300 ish of stuff that I've stopped using.
Livestock: about $600ish total.
So, maybe $4300ish total.