If you buy it by the gallon, TEA from The Chemistry Store is about $16 per gallon + shipping. It is handy stuff to have around, as is propylene glycol.

Anything can be dangerous. You can drown in a remarkably small amount of water. Most chemicals we use can easily be handled safely. The first time a child comes near the darkroom chemicals, a little application of knowledge at the seat of learning can stress the dangers.