Let me just get this out of the way before I begin: no, you won't be smelly if you make your own detergent.
There are several ways you can do this...normally I make liquid detergent, but in the interest of space (and time), I chose to make powdered this time.
I started making my own detergent about a year ago to save some money. While I have definitely saved money, I have noticed other benefits as well. First, the amount of chemicals in this detergent is pretty limited, so I really don't have skin issues like I did before. Two, I use less, so it lasts a heck of a lot longer, and its easier on our clothes- they aren't needing mending or replaced nearly as often.
A benefit to liquid detergent is that you can add essential oils or extracts to make a scent. I don't really care about that. In fact, over the last couple of weeks we used a bottle of Gain "Hawaiian Aloha" that I got for free with a coupon....our clothes smelled so fruity I was getting headaches. I'd rather smell like my body spray, anyways.
You will need:
1 bar of plain soap (ivory is what I used...)
1/2 cup Borax
1 1/2 cups of Arm and Hammer washing soda (different than baking soda- you can find it in the detergent aisle)
Grate the bar of soap on the smallest grate. It should look like fine soap curls:
Mix the soap curls with the borax and washing soda. Combine well, add 1-2 TBS per load of laundry. Thats it. Really. Store it in a dry place and airtight container. I store mine right next to the washing machine. If you want to add some scent, you can always use a soap that is lightly scented. Just don't use Olay....it doesn't work as well. I recommend Yardley's Lavender.
This batch usually lasts about 2 months for me. We would normally go through a container of Tide every two months. So, if I buy 6 containers of tide a year at $12, that's $72 a year (at least) on Tide. All of the ingredients to make homemade detergent cost about $8.....and last the whole year. It might not seem like a huge savings, but making small changes like this can add up to huge savings annually.This requires hardly any effort, either. Its like making $64 in about 15 minutes.