NETI POT!!!
It's gross, it's awkward, you'll hate it the first time or three, and don't let your partner tease you. I LOVE this thing. Warm water and saline solution run through your nose and clear everything out. Follow the instructions in the box and try it in the shower the first time until you get the hang of it.
This is worth it, I promise. I can get rid of allergies, colds, dry air, you name it, in 3 days tops, no matter how bad the cold is. My 2 year old is already learning how to use it.
You can buy it at Target, or any CVS/Walgreens, and I think the pot and solution cost $15??? at the outside.
Few people I've recommended it to have actually tried it because they're intimidated by the process but, oh I wish I had the words to explain how much better the cold season is now that the Neti Pot is in my life!
Good luck!