So I was putting a new tube in my front wheel, and while I was doing that I lost a springy thing. Are those important, and if so where can I buy one?

Schrader valve cores are More common in cars so go to a service station or auto parts store ,

Removable presta valve cores you go to a Bike shop.

Are you talking about the springy thing on the quick release?

They make it easier to mount the wheel by keeping the quick release centered. But, once the wheel is on the bike, they don't make any difference.

Ask your local bike shop about them if you wish.

Here are a few I was watching on E-Bay.

Bike Hub Skewer Spring ? 8 Pcs Silver | eBay

Yeah... they're easy to loose

These kinds of springs
https://bicycletutor.com/images/bike/...ase-skewer.jpg

Thanks m8.

Oh Those .. More convenient than required .. you can Live without it..

LBS may be able to Give you one from a trashed wheel.

Update: I put the tire back on and it works fine. No spring needed.