As you might figure, I don't do hairjobs with wigs, but I do have a lot of experience in wearing and styling them.

Everything you wrote sounds legit. Synthetic hair cannot replace human hair, and prices are rising due to ascending demand for human hair, but used or older wigs can be found for a cheaper price (try looking for a wig store which might posses older wigs that are no longer trendy (ones from 10 yrs ago can be found for significantly lower prices).

Of course prices change according to hair's origin. I find the european and russian hair the most fun to play with, but brazilian hair is thick and have a lot of volume and asian hair is also very thick, yet I find it less light.

Ponytails are nice, but have their downsides.

IMHO, as someone who wore synthetic wigs - big NO NO. using them for hairjobs will make them messy and "untangleable" in very short time.