Michael's craft store has TONS wonderful little inexpensive ($1, $2, $3) craft ideas that I've used with my 4 year old, wooden toys to paint, beads to string on necklaces, gosh, just too many to mention. Bubbles, stickers, sunglasses, flip flops, hair accessories, play-doh, band-aids (my son LOVES band-aids with the pictures on them - lol), fruit snacks.
Depending on how much you want to spend, some other things I've done is get things my son will need for summer, since his birthday is in January, so we only ever get wintertime gifts. LOL For instance, a swim suit, beach towel, maybe a couple summer outfits, sandals, swim floaties, pool toys, outdoor toys (balls, butterfly nets, sports equipment), gardening tools and seeds to plant flowers or vegetables - kids love to plant and see things grow, sand toys if they have a sandbox or will be going to the beach in the summer, etc.
And instead of a basket, we usually get a large plastic outdoor tub (got it for $5.99 at Target) to then use outside to hold outdoor toys through the summer! You could use a laundry basket or storage bin, if that works better for your needs after the Easter stuff is put away!
Hope this helps!