Go with whatever option you have the bits to support. If you want to spend minimum dough and already have a wheel, do whatever conversion method suits it best. If yo don't have a wheel, your LBS could build you up a SS-specific one for not much dough, but it still might be cheaper to adapt an existing wheel. Breaks down like this:
option 1: Can never be run fixed (at least not without resorting to some very non-standard methods), this may not bother you. Very easy to do however, and very cheap + easy to swap ratios. Like people have said, spacers are cheap as chips, as are the cogs. Cost = wheel + £10 max.
option 2: Requires £10-£15 labour cost to redish and respace for a decent chainline. Gives you the option of running fixed, but it still wouldnt be perfect as you dont have a thread for a lockring so it may not be safe to run fixed. Total cost = wheel + £15 labour + freewheel (£5 for a shit one, up to £40 for a pimp one)
option 3: Most flexible, but probably most expensive. Some places will build you up a wheel out of old parts for ~£20-£30. Getting cheap new bits may mean it costs upwards of £60.
To sum up, if you only ever want to run singlespeed, I'd go with option 1. Lots of relatively decent freehub-based wheels on ebay (or even new, you can pick up shimano wheelsets for £60), and the conversion couldnt be simpler.
Go with whatever option you have the bits to support. If you want to spend minimum dough and already have a wheel, do whatever conversion method suits it best. If yo don't have a wheel, your LBS could build you up a SS-specific one for not much dough, but it still might be cheaper to adapt an existing wheel. Breaks down like this:
option 1: Can never be run fixed (at least not without resorting to some very non-standard methods), this may not bother you. Very easy to do however, and very cheap + easy to swap ratios. Like people have said, spacers are cheap as chips, as are the cogs. Cost = wheel + £10 max.
option 2: Requires £10-£15 labour cost to redish and respace for a decent chainline. Gives you the option of running fixed, but it still wouldnt be perfect as you dont have a thread for a lockring so it may not be safe to run fixed. Total cost = wheel + £15 labour + freewheel (£5 for a shit one, up to £40 for a pimp one)
option 3: Most flexible, but probably most expensive. Some places will build you up a wheel out of old parts for ~£20-£30. Getting cheap new bits may mean it costs upwards of £60.
To sum up, if you only ever want to run singlespeed, I'd go with option 1. Lots of relatively decent freehub-based wheels on ebay (or even new, you can pick up shimano wheelsets for £60), and the conversion couldnt be simpler.