I find that the cheapest for me is to get the 365 brand at Whole Foods, liquid, I think it is 8 oz for about $22-23 or so. I refill a smaller dropper bottle from that. I think I paid the same amount for a 2 oz (or was it 4 oz? It's been a long time now!) dropper bottle. I get the pure extract. Watch out for the glycerate, it is a watered down version.
I also buy the single packets for taking with me.
It doesn't replace all sugar, but certainly reduces it dramatically for me. For example, I will use it to sweeten the fruit to make a fruit crisp but will use a little granulated sugar in the crumb topping. I can use it to reduce the sugar in some baked goods, but replacing all the sugar with stevia will result in some serious texture issues, and I find that stevia alone is not sweet enough to offset the bitterness of unsweetened chocolate...but I can reduce sugar use here, too.
ETA: I'm great, thanks for asking! How are you doing? Are you more stressed or less in your new apartment? Lonely or loving it? A bit of both?