BCF for ~<$20.
I understand why places don't do refills. It takes ages and when one factors in the labour and the cost of the gas there cannot be much margin it. Let's support those places though, because Swap n Go is a ripoff.
Well I was with you on the first bit and then you went and spolied it by directly contradicting yourself. Let's see shall we? Take an 8.5kg bottle and LPG weighs 0.54kg/L so an 8.5 holds fifteen and three quarter litres and according to my 3 way, 90L capacity, Dometic fridge manual it consumes 350g/day so an 8.5 bottle will run it for a tick over 24days. That's without running the gas stove or a gas HWS if you've got one. Interestingly you won't be trotting up the power and gas bill at home while you're away for 3 weeks or so and you need to compare that with the $35 for a Swap and Go or $28 to fill your own at Mitre Ten at Glenelg SA. Well I took the BBQ bottle there today for a fill but alas it was an 01 bottle so Swap and Go it was for $35. Now the last time I swapped it was 2-3 yrs ago at Bunnings for $28 as I recall. What a financial burden eh?
Now I could have bought my own bottle (for around $45 I spotted the other day) and then had it filled for that $28 and saved myself $7. Seven fills and I'd be in front so you can see how Swap and Go makes sense for the vast majority, particularly when those 'new' bottles for sale are already 2 or 3 years out of date sitting on the shelf I noticed.
So your local filler like my Mitre 10 can clearly make an earn on that 15.74L for $28 ($1.78/L) depending on the vagaries of LPG prices and PROVIDED they put in a big tank installation for thousands plus interest holding costs, plus paying for weights and measures periodic inspections, plus pump maintenace, plus power for running the pump, plus wage overheads while the filler is away from the till or serving other customers, not to mention having to go to the appropriate course and be 'qualified' to fill them. Say 10 mins per fill or 6 fills an hour average and right there is around $50 an hour in total wage overhead. Or the alternative is Elgas tells the proprietor they will supply a nice galv cage (Regulator approved storage with all signage plus requisite fire extinguisher) and they'll stock it regularly and he'll make say $10 a cylinder for his troubles. Whaddya reckon, seeing as how the customer is not allowed to fill the bottle himself like he can with his LPG vehicle?