Meal planning was a really big one for us...
Lidl has some good stuff (wipes, nappies etc)
Primark, Matalan and Asda all good for clothes
Get a picnic rug and go for picnics rather than pub lunches (whilst the weather is good)
Shop around for utilities - make sure you're getting the best deals on gas, electric, phone etc
My dd is similar age to yours and has loads of toys but barely touches them... A few plastic bowls and wooden spoons are far more entertaining. Balloons provide hours of fun as well. Join the library for books (also good to go and spend an hour or so on a rainy day in the children's section)
I used to spend loads on toiletries and beauty products (Clarins etc.) - some supermarket stuff is great. Stock up on 2 for 1's on shampoo, toothpaste, deodorants, loo rolls etc)
If you're not up to making your own cards, then buy a pack of generic cards (but don't put them somewhere "safe" and forget where they are and buy new ones - not that I did that of course ). Same with rolls of giftwrap. Books are great pressies for children and Red House is great reasonable on line website
Photos of dd are always popular as adult pressies (for gp's etc.) - frames are cheap from Matalan, Primark etc. and I use snapfish for prints.
Don;t buy magazines or newspapers - go online and read them if you want