You can get the Joie tilt for about £60, that's cheaper than the majority of forward facing car seats. To be honest if you are looking at a forward facing seat for around that price or less, it's probably of extremely poor quality and I would not recommend you use it.
But -
Whatever seat you use, use it as safely as you can. Read the instructions, install it correctly. A cheap car seat is better than no car seat at all. An improperly fitted car seat is better than no seat at all. A rear facing one is better than a forward facing one and this is particularly important before 15 months (why the legislation has changed) but a forward facing seat, properly used and of a good standard, for an older child will afford excellent protection in a crash. A rear facing one is significantly better, but it doesn't help to shame people.
A six month old should not be forward facing, and the only reason they legally can is because the weight classes were drawn up in the 80s, when using any car seat at all was fairly unusual. The newer 15 month rule will eventually cover all seats, but doesn't yet because policy makers are not interested in making life hard for parents but for making car travel safer for children.
I would expect to see the age for rear facing minimum increase in the future, and I'm glad that many parents are now aware of the risks of forward facing under a year. Personally my goal is 3, but I would consider FF from about 18m if other factors made it the more practical choice.
I do think RF is more accessible than most people realise though and I'd love to correct some myths! Tiny cars generally not a problem. Rear facing toddler seats take up less space depth wise than infant carriers, and people fit these in fine. They are also designed with better leg room, so children aren't folded up like concertinas! Although actually many of them find that position quite comfortable.