I had rented an Air Products oxygen cylinder for years, but when the advice of the next year's rental came in at £120 I decided that things had to change.
Admittedly this was a large cylinder, but I hadn't exchanged it for 9 years or so and it was still two-thirds full, so I could afford to downsize and hopefully save some cash. In addition to the annual rental, Air Products impose a handling charge when exchanging the cylinder – expensive when collecting and even more expensive for delivery. Another annoyance was that their agents are now few and far between.
So, I needed to look for something smaller (and hopefully cheaper to rent). I'd started thinking about the future – maybe I'd go back to BOC and see what they could offer – at least they had a more suitable network of agents than Air Products.
Then I found a reference to a company by the name of 'Adams Gas' on this forum which made interesting reading. Adams are based in Margate, Kent and operate through distributors – there are a number of these in Kent and some further afield. The interesting thing about Adams is that you don't pay an annual rental charge, neither are there any handling charges. All you pay is an one-off up-front payment which is fully refundable at any point in time should you no longer wish to keep the cylinder – this charge is currently £55.
Looking at the Adams website – http://www.adamsgas.co.uk – I found that I could get an oxygen cylinder for £36 (inc VAT) plus the up-front payment of £55. Admittedly the cylinder is much smaller than the one I had and it is filled to a lower pressure (137 bar as opposed to around 200 bar) but it appeared to be a good solution to my problem. The real test will be when building a boiler and seeing how many refills will be required, but this only happens occasionally and I'm already in profit.
Adams list various gases under the heading of 'Hobby Gas' which includes MIG welding mixes as well as the oxygen – they don't offer acetylene. Their cylinders use the same regulator fittings as BOC, Air Products and Air Liquide, so no problems there.
Depending on where you live the Adams Gas may also be worth considering.
Good luck.