Like you I simply can not afford to take 4 piggies to the vet every time their nails need clipping, so I just had to make it work.
I also watched several You Tube Videos, and have discovered that every pig has their own preferred position for nail clipping.
Eddi and Lucy are pretty laid back, and DD1 pops them onto a cushion on her lap and feeds them something super tasty (a large dandelion leaf usually does the trick) while I dive in and clip everything on one side.
Then she turns them around the I do the other side.
Oreo is a little harder as she need to be held firmly, but is still do-able with just myself and DD1 (who is 12 and very competent with her guinea pigs).
Ruby on the other hand is a different story.
As soon as she sees the nail clippers she starts chattering her teeth.
In all honesty she is a total nightmare.
DD1 holds Ruby around the middle in a 'begging' position, with her bottom resting on a cushion and her back resting against DD1.
DH (oh yes - Ruby needs 3 people, including 2 adults to clip her nails) has a carrot or piece of apple which he keeps firmly in front of her mouth at all times.
I sit directly in front of DD1 and try my best not to get bitten if DH fails in his mission to keep Ruby's mouth occupied at all times.
Let's just say it would probably be funny if it wasn't actually me that had to do it.