Hi, I try t answer your questions.

1. I don't know if you are interested of buying it. It's at a low right now but there is active development, so we could see a rise in 2018
2. Yes quite easy and efficient with Harddrives. You PreCalculate nouces and the "mining" is looking for the closest nounce to a given difficulty, The one who hat the closest wins the block and around 1400 burst. For mining you should have at least 10Tb space left
3. You can buy it at many different exchanges. Poloniex for example.
https://coinmarketcap.com/currencies/burst/#markets

It is interesting for mining, because it is very cost efficient. I for example have old drives from Servers wich I refurbished to burst mining with a NUC under Linux. (For nounce plotting [generating nounces] I use a Windows system.