dont buy a co2 bottle you then become responsible for certifying its safe to use and may have difficulty getting a refill. And avoid co2 monthly premium contracts again an expensive option.
be prepared to pay a returnable bottle deposit upto �ã50 just the same as a calour gas bottle.. and the �ã15-�ã25 per refill, a 6,5kg bottle of co2 is a year or 2's worth barring accidental losses.
ebay for ex pub dalex styled taps for a fiver or so, tho the cheaper taps tend to have branded handles ;( the dalex style taps are much better to use than the fancy shiny metal types as you can simply unscrew the spouts for a soak between servings and needednt faf about flushing the spouts or capping them to keep the fungus gnats away.
the hidden costs can be the number of JG fittings used to connect upto thinner 3/16" microline which is very useful in reducing keg pressure before the beer hits the tap.
a cheap heating element can be a 100W incandescent light bulb either painted black or fitted into a clay plant pot to hide its light
I can offer you an STC1000 v1.0 without solderpads for upgrading for a fiver plus actual pnp if interested, i bought it to reflash but while its the right model and the pcb has the 5 holes drilled for the reprogramming header, they are missing the metal soldepads to make an electrcal connection so I failed to reflash it so its still using the standard out of box control system.