DIY Modular Seating - Easy build and you can build it/arrange it to fit your space. For the deck?
Easy shelves with leather straps - pretty easy shelving idea. Should not cost much either!
These DIY rope ottomans are so cool! Students would love using them as seating, and they'd match the decor theme in your ocean(blue rope), garden, nautical, and farm classroom themes!
14 Pinspired DIY Wall Art Tutorials - GleamItUp (do something like this on one wall, painting, like kristy)
Decoupage Map Letters for wedding decor.
Living room end tables. DIY Tables: Home Depot has whiskey barrels for 30 bucks & Bed Bath & Beyond (& Joanne, etc) has glass table toppers for 9 bucks. This is a great idea for DIY outdoor tables!
22 Simply Splendid Decor Baby Nursery Ideas to Consider