Get it from your vet, I get mine from my vet cheaper than I can at the local supply store. They will also tell you how to dose it. Usually 1 mL per 5 lbs of body weight. I got 250mL for $25 and that will go a long ways.
Yes there is a big difference. My Vet said on the horse paste Panacur only never use the other ones except maybe safeguard which is the same as the panacur . They told me 1cc per 5lbs of weight. This comes out to a higher dose than you would use for a 1000 lb horse believe it or not. I was really shocked. I do 12cc per 50 lbs.for 3 days and repeat in 14 days for any eggs.None of my dogs have ever gotten sick but you should ask your Vet that is what my Vet told me.
I only use the paste or tabs. The paste is 1ml for every 5lbs of body weight. I use both panacur or safeguard, same active ingredients there. I've never used the liquid so not sure. The tabs have easy dosing rate, different size/amount for the size of the dog.