Morton TenderQuick isn't a curing salt--it's a dry cure (in other words, it's curing salt mixed with other ingredients).
Curing salts are the same. DC#1, Insta Cure #1, et al., are all the same thing: 93.75% salt and 6.25% sodium nitrite. Most are tinted pink to distiguish them from ordinary salt (they should only be used as directed in a recipe and stored safely out of the reach of children). Also, all the curing salts that are used for dry-cured sausages (DC#2, Insta #2, etc.) are the same as well--they have the addition of sodium nitrate.
TQ is fine but that vast majority of sausage recipes are written with curing salts in mind. A measure in a recipe for curing salt is not interchangeable with TQ as TQ also contains sugar, propylene glycol and sodium nitite and nitrite in proprietary amounts.
I prefer to use curing salt alone for sausages and to make dry cure blends (salt, sugar, sodium nitrite--for bacon, for example) myself as it is easy to make, one can make a batch ahead of time that can be stored for months (so whenever the need to cure pork belly grabs you it's available), it's cheaper to make oneself, and I can skip the propylene glycol and the nitrate as neither are necessary.
I get my stuff from
here as they're cheaper than most and reliable. I get casings from them too--and innoculant. Grab some dextrose as well (search the the site for it, I forget its category) if you decide to get curing salt and/or casings from them as it's finer than table sugar (so it blends better), not quite as sweet, and cheap to boot.