To "blow money" on something, means to spend it frivolously or to waste it. For example: "He blew over $5000 dollars on gambling last month!" "Splurge" means to spend money freely, but usually for the sake of enjoying something. For example: "I'm going to splurge today and get the extra large sundae, instead of the small vanilla cone." - In this case, the person decides to spend more to enjoy something that they perhaps don't usually get. "Piss away" means to waste. This doesn't always refer to money, but it can. For example: "He pissed away his time browsing the internet, rather than working on the project. Keep in mind that "piss away" is a rude expression and is best not to use it among strangers; only around those that you know won't mind hearing you speak that way. Does this make sense? If you still don't understand, please let me know and I will try to explain it in more detail.

1. "You shouldn't blow all of your money on shoes." --> spend something (usually money or time) on something you shouldn't 2. "We splurged and bought the more expensive tickets." --> use more money than you wanted to 3. "I pissed away my last paycheck on useless things." --> spend something (usually money or time) on something you shouldn't, this is more vulgar and offensive than "blow money"