I looked on Lakeside.com, as they have some decent stuff for affordable prices. Here are a couple things I've found:
Storage Solutions
Colorful Organizers
Also, I have found Big Lots to be very affordable for rubbermaid containers. I like the 18 gallon totes - not the super huge ones, but the smaller ones, as they are easier for me to move around. I paid $5 for mine, which isn't too bad. I would take $5 from our grocery budget once a month so it didn't really affect much and buy one a month til I had what I needed.
Check your local dollar store & thrift store for things you can repurpose. Grab a utensil holder to put in your junk drawer and separate things - matches, lighters, batteries, etc. or use one in your bathroom for hair accessories, razor/razorblades, nail stuff. Ice cube trays work well to contain little things and separate accordingly. Sweater bags are great underbed storage for out of season clothing or extra blankets/sheets. Sweater hangers (the ones that have box openings stacked on top of each other and hang vertically from a closet rod) work great, not just for sweaters, but for diapers/baby & kids stuff, lightweight food (boxes of stuffing, pasta, marshmallows, chips, seasonings) paper goods, light bulbs, extension cords. They follow the "think up" rule - go vertical to take advantage of unused space. Every dollar store I've been to also has plastic containers - tons of different sizes. Plastic washbasins are great for under the sinks - I have one under my kitchen & bathroom sinks to hold cleaners, sponges, etc. I can throw them in the dishwasher to sanitize/clean. Grab a hanging shoe organizer (with a multitude of pockets on it) and stash bathroom supplies, socks, shoes, pantyhose, office supplies, kid stuff, crafts, etc in it.
Use what you have around the house - shop at home first. Cut cereal boxes to make magazine/paperwork holders for your desk. Have friends or family with babies that buy boxes of diapers? Ask if you can have the boxes.
Cardboard boxes work wonders for basic storage. If you work (or your DH does) at a department/grocery store, ask if you can bring home some boxes they are going to recycle. They always let me do it at Walmart when I worked there years ago. Shoe boxes were the best!
Put your bed up on riser blocks (like the picture below) to add space under your bed for additional storage.
The biggest thing is to declutter FIRST - then figure out what you need for organizational tools. That is the top tip of the Clean Sweep organizer. Last summer I took inventory of all the organizational tools I'd need to redo my desk area. But then I started decluttering and once I was done, I really only needed about a 1/4 of what I had figured.