Slime Rancher

You earn newbucks buy selling plorts on the ranch. Plorts sell for different values based on type and the prices change over time. Pink plorts are the easiest to find but sell for very little. You get plorts by feeding foods to different slimes. Here is a list of the slimes and foods they enjoy.
Pink slime (any food)
tabby slime (meat/hens)
rock slime(veg/carrots)

Those are the first three slimes you will come across. Feeding plort to slimes can form largo which when fed give two kinds of plorts. Making combos such as tabby/rock can give a lot of money and are easy to feed. This achievement just requires a lot of farming. You can also feed slimes that are in the wild and sometimes they will eat on their own creating plorts in the wild. Upgrading your vacuum to hold 30 of each item will also help with collecting plorts.

In order to get this achievement and all other "Earn over --- newbucks" achievements, there's a simple strategy to complete this quickly and pretty passively.

1. Make two corrals with the high wall, air net, auto feeder, and plort collector upgrades.
2. Fill both corrals with 10-15 largos. Preferably late game slimes like quantum/crystal and
dervish/mosaic largos.
3. Use their favorite foods to gather twice as many plorts. All favorite foods can be found in
the slimepedia. The favorite food of either half of the largo will give twice the plorts for both
halves of the largo.
4. Harvest to your hearts content! You can complete this process quicker by sleeping until the
next morning, refilling the auto feeders, emptying the plort collectors, and going right back
to sleep!

Here's my video for every achievement if you'd prefer. Skip to 4:27 for Fortunate.
Happy Hunting!

As this achievement has a further progressed version at 100,000 newbucks, I would reccomend you just play the game in the start and get this naturally. But if you really want this right away, I would recommend you use this method with and early slime, like the rock slime, right away.
Method for those who are impatient: The easy way to earn money, and this will help for getting to the Golden Sureshot upgrade at club level 22 as you need hundreds of thousands of newbucks to get there, is done by playing the market. This is easiest if you have Rock Slimes at low levels but this can be done with really any slime. Well... I wouldn't recommend Crystal, Pink, or any that are primarily meat eaters as chickens can be annoying to get a hold of in mass, and odd onions can't be grown as easily. The more valuable the slime though, the quicker it will be. Start setting up corals and fill them with your selected slime, I only had five corals full of about 15 slimes a piece. Upgrade the corals as you make them with higher walls, an air net, and a plort collector for greater simplicity. For each new coral you build, create a garden with at least the first two upgrades. In this garden grow whatever your selected slimes favorite food is, the Wiki Guide for this can be found here (Heart Beets for rock slimes)> http://slimerancher.wikia.com/wiki/Food. Fill the rest of your spaces with fully upgraded silos which you will fill with the plorts of whatever slime you're farming. Either go do something else while checking back in occasionally to empty collectors/harvest food, or rest until morning to speed up the process. The hoarding of the plorts will drive up the price and once you feel the market price is high enough, sell all the plorts as quickly as possible. Repeat this process a few times while potentially changing the slime your farming if you feel like it and you can get money pretty quickly. You can also make your slimes largos and use the secondary plort to sell constantly throughout to afford expansions ventures if you so choose, but don't feel obligated to do that. Using this method, you should be at 100k in no time.