When did I say anything about math? That was you. I know the math. You need to play to win, so I play. Plus, it's not like you're losing money in real life. You're losing money that you can make back in 5 minutes by breaking some melons. If you don't like to gamble, that's fine.
I personally think the best way to earn 150k fast is mining - and then mining some more. If you need a break from that, then farm for a little while and then get back to mining. I am happy to see you say that lotto is not an option! That is a great first step in being successful.
First, I suggest having another user help you save. Something like this: www.tinyurl.com/oyster-max Then, I suggest finding a pumpkin farm, since that doesn't require a star tool, or, a cocoa/wheat/potato/carrot/sugar farm, since they require no special tools at all. Farm until bored, then keep farming. Another option is fishing. At $10-25 a fish, plus the EXP you can sell, it adds up pretty fast. Finally, ensure you are putting money into the bank sign, and, should you play lotto at all, win or lose, give yourself a penalty of a higher amount to deposit in the sign. However, a lotto ticket can be a reward. 25k in the sign = 1 ticket allowed. It is not hard to save money if you are smart, give yourself rules and guidelines, and then follow them.
Lotto, done. . Just kidding. I would suggest farming melons with a melon sword for about 7.5 hours or mining for the same amount of time.
Take loan on the old load and then go and farm cocoa, I havent seen fastest way but someone might tell you it.
You're not going to like it, but its going to take you many hours of farming or mining to make the money. if there was a 'quick way to make 150k', everyone would just do that. there isn't.
For exact numbers on mining: I am a very experienced miner, having played Minecraft since alpha 1.2, with a heavy focus on mining regardless of my current server. That said with with the mining world kind of ruined at the moment, and my having pyro+ and an eff5, unbr3, fort3 pick, I made exactly 192k in 4 days mining around 5 hours a day. I'm sure your numbers will vary (especially if you die in lava due to not having pyro+), but likely they will resemble mine
use a pumpkin axe they are cheep and u can get 10k an hour or u can use a max fort pick those cost a bit more but make more. If you have a star tool you should use that though.
lotto is your friend she is also your enemy you two will mix and blend if not, then let it be for lotto is not fair but neither is a bear deep poems by deep people 2014