>>10844973
>find instructions online
this is actually really helpful, especially when figuring pricing. start by looking at the yarn they used/recommended. 4 different colors/balls, £8.50 apiece brings the cost up it £34 just in materials. this yarn is on the nicer side, though, so you could feasibly cut the yarn cost in half.
the next thing to consider is skill/labor. the pattern is labeled as "intermediate" by the author, so maybe not a good first project for a knitter but definitely feasible for anyone with some experience. if you wanted to, you could try looking into local knitting circles and see if anyone is willing to take a commission on this (offer to buy the yarn so you get the right colors etc) or you could try learning to knit yourself. knitting really is not very hard, the biggest separator in skill-levels is not whether something can be done but instead how long it takes and how consistent the tension/knit-sizes are. if you really wanted to do this on the cheap, you could buy the yarn yourself for maybe £17, get some needles for another few pounds and spend a month or so practicing technique and unraveling before starting in on this project.
a lot of words for not that much advice, but general gist is consider yarn cost/cost of construction (you say you could go up to £30 but even doing it yourself you would be saving <£10 from that figure) and that you have to also pay for labor. talking to someone local and in-person who will do commissions will be better since you can get measurements etc. taken to have them be a better fit. if you buy the yarn and offer someone money to do it, though, you will probably still be looking at ~£40 total to compensate them for their time so £50 isn't that unreasonable.
>one loose thread
yes, a single loose thread could unravel the entire glove. BUT not if you spot it in time. the pattern makes mention of "weaving in ends" which is something you can do yourself