Sprinkle is in the UK, I'm in the US, that will decide what meds you can get & what they're called.
I understand being young & poor. I was trying not to be too awfully negative but the only time I had camallanus (in 40+ years) I lost 5 of 6 fish even with meds, special gobies that made it worse...But this WILL kill your fish without meds. Now, the insensitive pragmatist in me says the cost of new healthy fish (eventually, after
lots of hard work to rid your tanks of this terrible plague) will be less than the treatment costs... & that's iffy at best. The humane fishkeeper in me says do the best you can, but don't wait.
No, there isn't a cheap & effective treatment. I wish there was.
This is very hard for me to be so blunt (tearing up,
sniff). But if you choose not to treat your fish you will have to tear down & really disinfect your main tank & the quarantine tank too... & then start over with cycling etc...but you may have to do that anyway...A very difficult choice for you. I'm very sorry, there are no good answers.