buy her a 100bucks bag of marajuana, thats about half oz where i come from, she'll be high as a kite and really happy, thats what you want your mum to be like right?
Invest in link building and get good links and make a lot of money and leave presents to a few months latter.
Take her to dinner and give her a watch as surprise then tell her that its your first entrepreneurial income. Definately she will more happy then
Gr8 suggestion.... i think this is the best thing u can do ..... and if that amount is low then reinvest for sometime and get it more for the needful things.