Cassette freehub vs freewheel conversion

so, I've been getting 'sheldoned up' and I'm planning to embark on my first single speed conversion, using a couple of old (1980s), geared road bikes. I would like to spend as little as possible, but get relatively safe/reliable and decent results.

There seem to be three main options when it comes to sorting out the rear wheel.

1. obtain a wheel with a cassette hub and fit a single sprocket with spacers
   
2. re-dish a freewheel-based wheel and thread on a bmx freewheel
   
3. build a new wheel from scratch
   
   

However, I haven't been able to find much information on the relative pros and cons of these 3 methods (mainly in terms of final result and cost). I would be quite happy to spend some time learning to build/re-dish wheels (and have already found plenty of related advice on this forum), but what would the advantages of this be when compared to option 1 (which seems like a cheap and adequate solution)?

any advice would be great! cheers.

I got a wheel built with a normal hub, like number 2 option really, and had it spaced out with some old bearing races, it was a cheap option as it only cost the amount of a wheel lace up. looks a bit wierd with the bearing races, just means you can get good wheel alignment without buyin a specific hub. Don't know if loads of people do this, but it seems to work ok. Then i just put a bmx freewheel on it.

there are no real advantages over your option 1.

if you want ss only, it's the best way to get a decent chainline, and cheaper to change cog size if you want to.

Most freewheels seem to get slated as liable to kill you eventually unless you spend some coin whilst a road/MTB freehub wheel seems to be unfugwithable.

You can get the spacers for next to nothing I I've got some 18/19 tooth shimano splined cogs from On-One I'd give away to anyone who asked nicely.

I just left my geared wheel as it is, took the 8-speed cassette off, slid a couple of gusset spacers on with the cog, shortened the chain, screwed the tensioner on, and viola, jobs done.

You might need to swap the front chain-ring over to the middle to get your chain-line right.

My chain-line is a bit off but with some luck some spacers should sort it out

here's mine

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.

cheers everyone!...some really helpful responses. I think I'll go for option 1 first, then perhaps if i get adventurous I might explore option 3 with a flip-flop hub, so that I can give fixed riding a go....we'll see! I'll keep you posted on my progress, and I expect I'll be back here with more troubleshooting questions along the way. thanks again!