It's a bit on the pricey side, but not way overpriced
Mine cost £18 I think, but that was a bargain.
Bear in mind they're very hard to acclimatise, they have a reputation for fading quickly soon after buying them, as they dont travel well. Best to buy from somewhere that's had them in for a few weeks and fed them up after shipping.
They also love fast flowing water with plenty of aeration - mine sits in the flow of the bubbles from my internal filter most of the day
They're apparently quite territorial as far as plecs go - but mine's only 2" too so cant really comment on that - he certainly doesn't seem grumpy but there are a few other plecs in there, all of them bigger.
One thing to remember with them is that they're not algae eaters - they are omnivores - and although they will eat some algae, apparently (although mine doesn't!), they also need some protein added in their diet too - shrimp/squid/mussell pellets go down well here (but there are loads of other alternatives others will mention I'm sure), as well as the main staple (good quality plec wafers/tablets and veggies).
I'm sure there'll be more knowledgeable folks who will answer with more info - I'm new to nugget keeping having only had mine a couple of weeks.
Edited to add - might help if you post tank size - as sail fins (gibby?) and commons can get very big (commons 12-18" and gibbies up to 2ft!), and nuggets - depending on which type they are - can reach anywhere between 7 and 16"
You'll need a hefty tank for all three.