Getting back to you on refrigerant prices, Reefer -Tek.

On 'black market' , r12 can be bought in HK city for approx USD5/kg whereas r502 avail here for around USD20/kg. Coming in from mainland and former USSR 'rebottling' plants apparently.

PS ! are you still in 'exile' or RE Purgatory? when do u get out ?
Liked A-Z's multi temp thread b.t.w.

regards
T-P