Help! Cheapest / Quickest way to make this single-speed...

i've also recently been looking to make the move over to a single speed, decided just to go a few weeks without changing gears to see how i liked it. my legs feel much stronger already!

as i have verticle dropouts on my frame i couldn't just straight up remove the rear deralieur and some links from my chain as there would be no way of getting the chain nice and tight. so today got myself a nice spring loaded chain tensioner and got rid of all the clunky mech. only cost me £17.. hope it helps

You can buy a White Industries ENO rear hub which allows you to tension the chain without a chain tensioner.