Hi: I am in the US and I can get a box of 100 tea bags from Aldi's for less than $2.50. They only sell one brand. It's strong, plain, nonfancy tea. I prefer Twinnings tea bags though and look for sales. I find Twinnings bags are a good midpoint between the fancy stuff (which I also like) and the cheapest stuff.

Just in case you don't do this already, I highly recommend using a tea pot. If you just put the tea bag in your cup you will, obviously, be using up 1 bag every time you want a cuppa. Using a pot makes the tea bags go further. I use 1 bag for half a pot, which makes 2 cups plus a skoch, or 2 bags for a whole pot which usually makes 5 cups of tea. On occasions when I haven't had a teapot, I've made do with a cooking pot.

If you want your tea to still be hot when you get a refill, a tea cosy really does work. If you don't have a cosy, wrapping the pot in a tea towel also works (hence the name).

As well, you can warm the pot first. After your water boils fill your empty teapot with the boiled water, count ten or twenty, and then empty it. Or just fill the pot halfway and swirl the water while you count. Then put your tea bags into the empty, warm pot and pour your boiled water over them. I can generally get a hot cuppa 30 minutes after making tea and a warm enough cuppa after 45 minutes.

Using a teapot, warming it, and using a cosy/tea towel not only make your tea bags go further, they also make, IMHO, vastly better tea.

I have experimented with saving and then reusing tea bags. I think one needs to be of the opinion that bad tea is better than no tea for it to be worthwhile.

Cheers, Heloise