I've gotten envies from Shoppers Drug Mart here in Canada because lots of people buy cards and forget the envies. Also from Hallmark stores but they are less generous as the ones around here package them up for sale WAY too expEnsive.
You can make small faux brads by shaking EP on glue dots and heating gently. You can get jumbo Brad too from those 1/2" dimensional glue dots.
I save small bubble packaging for shaker cards and large ones for disposable paint containers for acrylic paint or water pots for watercoloring. I often don't even throw them out but wash them to use again
Hot chocolate tins, chocolate boxes and other nice boxes, tins and jars make great treat or gift packaging. I open pop-top cans (soup, condensed or evap milk) with a can opene from the bottom, wash, dry, decorate and fill then glue the bottoms back on so the recipient can 'pop' the top.
I save the acid free cardboard from SU! dP packs and use for creating or reinforcing 3-D projects.
Buy large, full flowers on sale, separate the petals, they are formed in layers, and only use a few layers per card.
Use lighter weight cardstock for mats saving the heavy stuff for 3-D projects or card bases. Clear Dollar stamps sells 'layering weight' cardstock for a good price.
Use art qualiy tracing paper instead of vellum. It is easier to emboss, still see through and you get a whole roll for the price one pack of vellum.
Save your scraps. Nichole Heady made a great scrap organizer from her clear stamp boxes. If you don't have any, you can buy card set boxes in lots of places and use those. I also save scraps in folders by Cropper Hopper. Each folder has two pockets to hold scraps. I use one for medium scraps, one for large scraps, even half sheets and the small ones go in my organizer. I never cut into a full sheet for a small mat, tag or punch/die cut. Saves me tons!
If you have crafty buddies, see if you can get together to buy stuff in bulk like small tins for teacher's gifts or similar. I've got a whole box of tins I am slowly using up. They are exactly like tins that retail for $2.50 but I got them for 50c each with shipping about 65c. Same for test tubes which make great gifts.
Buy things you might use a lot of in bulk like ribbon or twine. I've gotten full spools of ribbon from the Stamp Simply Ribbon Store for wedding favours and it was very fancy ribbon for a fraction of the retail value.
Buy foam dots in bulk, I get mine from Jody Morrow of the Addicted to Ribbon blog and they are great quality for cheap.
Get your Copics at a discount. COPICmarkerS.com - a Period Style website
has huge discounts everyday. Did you know you can buy empty cases and build your own custom sets which ship for free as do all sets?
My $ store now carries Kaisercraft-esque pearls! Same packaging, similar colours (tho fewer of them), same sizes and they come in white!!
Same $ in other ways so you have more to buy the fun stuff. All of my small bellies live in $ store packaging, 25c per container. They stack with one screwing in to the one below it. They sell at Michaels for almost $4 for 5 or 7. Compact, they stack way higher than how they sell them and they are clear for all his who forget it if you can't see it!
I do lots more too but most have been touched on by others. I really like the tip to use excess chipboard as dimensionals. Acid-free unlike some other things I've seen suggested and that makes me happy!
Try getting some stuff at discount, deal-a-day sites like CraftySteals.com and a couple others I can't remember the exact names but if you google 'craft deal a day' I'm sure you'll find the others and maybe more! Discounts of over 50% are pretty standard but I've gotten over 75% a couple times.
Hope these help!