This is where I was nearly 10 years ago! I didn't want to spend a lot of money on an overlocker as they were a complete unknown to me, but I could see that they would be good for knits and seam finishing.
I went with a Singer from Lidl for £99. (Lidl have also got an overlocker in stock this week). My machine was very good, but from other reports on this forum, other people weren't so lucky. I used it a lot and after five years or so decided to upgrade to a Juki654DE at just over £400 at the time. I sold the Singer, which was still going strong. It had served its purpose as a starter machine.
I wouldn't get too excited about the 2-thread stitch. When I tried it with the Singer it never worked satisfactorily as it relies on a little plastic spreader thingy, which keeps falling off. When I bought the Juki, I asked about 2-thread stitching, saying what I'd found, and the dealer pretty much admitted that it doesn't ever work very well on any machine. Maybe the TOL models are different. In any case I've found 3-thread or 4-thread work well for what I do.
My machine came with an elastic gathering foot which I haven't used to date. It's still in the packet. I don't use any additional feet, but your needs will depend on what you are intending to sew.
Threading is fiddly, but can be avoided much of the time by pulling threads through (loosen all tension dials, snip off the old threads near the cone, tie on your new threads to the tail and gently pull - you might need to rethread the needles if the knot doesn't want to go through the eye - then reset the tension). When you do need to thread the machine from scratch, take your time, use the tweezers provided and do it slowly and methodically following the handbook and it will be fine, if sometimes exasperating! YouTube can be a big help.
Generally I would say go for it if you sew knits. An overlocker is a game-changer.