I started to collect these in the tense weeks waiting to hear back from my first batch of interviews. You can clean just about anything with baking soda and vinegar, but there are products we use regularly that are sold in very small quantities (for marked-up prices) at bodegas. While we're on the subject of recipes:
6 tablespoons baking soda
2 tablespoons salt
2 tablespoons glycerin
20 drops peppermint, spearmint or cinnamon essential oil
Combine and store in a small container.
Homemade dish soap
1 cup liquid Castile soap
3 tablespoons water
a few drops essential oil (if using unscented Castile soap)
Combine in a vessel of your choice, mix well, and use.
Homemade dishwasher detergent
1 part borax (see description of borax here)
1 part washing soda (see description of washing soda here)
distilled white vinegar
Homemade laundry detergent
1/3 bar Fels Naptha or other soap (link above includes specifics)
½ cup washing soda (baking soda is, sadly, not a sufficient substitute)
½ cup borax powder
A small bucket, about 2 gallon size
Grate the soap and put it in a sauce pan. Add 6 cups water and heat it until the soap melts. Add the washing soda and the borax and stir until it is dissolved. Remove from heat. Pour 4 cups hot water into the bucket. Now add your soap mixture and stir. Now add 1 gallon plus 6 cups of water and stir. Let the soap sit for about 24 hours and it will gel. You use ½ cup per load.
You can also make your own sunscreen, lotion, or bug spray.
Good luck constructing your Ikea furniture. Check out HousingWorks or the Brooklyn Flea for already-constructed furniture.