The second (and cheaper) path assumes that you have the design and dev chops yourself to build your dream software. Naturally, it’ll take more time to get your product off the ground, but being able to bootstrap the development of your software lets you retain more ownership in your business and be more in control of your path, making this a lower-cost, but higher time investment to make money selling apps.
People are always looking to have their cars washed and detailed. You could be a mobile car washer and detailer without having a permanent location. Reach out to people you know or make some flyers and put it in your neighbors' mailboxes. If you want to get serious about it, prop up a one-page website or give out business cards. You can make money quickly doing this.
Mechanical Turk is Amazon's take on micro-jobs. These are small miniscule-jobs that you can do for other people, which they call HITs, or Human Intelligence Tasks. These are super simple tasks that anyone can do. Some examples are listing off some URLs with certain kinds of images for one cent, or recording a few phrases with a microphone for 6 cents.
Hunt for under-priced used books that you can sell online. Download an app that reads ISBN numbers so you can scan the barcodes on books. This will pull up the book’s current price on Amazon so you can see if it’s worth trying to resell it. Then, visit used book stores, thrift stores, and garage sales to look for high value books. Post the books for sale online using sites like Amazon or Ebay.