That's a really hard question since you don't give any indication as to how much risk you want to take.....ie...restrict yourself to so called blue-chips or take a bit of a punt on some spec stocks or a bit of both
But either way, assuming you will want your $30k back in 6-8 months to buy a house, atm I wouldn't recommend to anyone to put their house deposit in the share market assuming they are largely risk averse with it.
Imo there are too many dark clouds on the horizon that could potentially turn into storms in the next 6-12 months.......rising tensions in the Middle East, rising oil prices, rising interest rates, inflation potentially rising should all help keep a lid on our market for the forseeable future imo.
Personally, the safe play for me would be to lock in at least 5-6% in say an online saving account for the next 6-8 months and also be assured the $30k will still be there as opposed to putting it at risk in the hope of a slightly better return in the markets........but at the end of the day it's your call and good luck with whatever you decide.
Trading/investing in the markets should be a part of your overall investment strategy not your only strategy particularly if your home is your first priority.