Personally I would probably avoid those pellets - the first ingredient is wheat, so although they seem quite a good price, you are paying for pellets bulked out with something our piggies shouldn't be eating.
I know price is important with lots of piggy mouths to feed, but you also need to feed less of a high quality pellet, so that is one saving, versus cheaper foods where you piggies will eat a lot more to get the same level of nutrients.
Another possible issue with the JR Farm more C is that it has quite high calcium levels. If you piggies eat too many pellets and have problems with bladder stones it will end up costing you a lot more in the long run, than feeding a better quality pellet from the start.
You can make pellets go further by foraging for things like fresh grass as often as possible - over the Summer my piggies have eaten very few pellets because of all the grass they get (although that will change soon!).
I bulk buy Versele Laga Cavia Complete and split it with another local guinea pig owner. Mine eat very few pellets so I don't need a huge sack, but by splitting the sack with a neighbour we get a better price per kg.
There is a good chart here comparing different pellets:
Nugget Comparison Chart
