All you need are some things you probably have around the house already so this could be free to do but has an awesome impact!
This works best on a day when you will be apart most of the day. On that morning, leave a stack of envelopes for him somewhere (by the front door). Put the first envelope in the bathroom for him to find when he's getting ready for work (this one will have instructions in it). On the front of each envelope will be the time of day, one for each hour from 7am-10pm (or whatever time fits his schedule). Inside each envelope put a special message of love written by you and even pictures or simple little gifts.
Here's some ideas:
Honey, by the time the day is over, I want one thing to be perfectly clear in your mind-the fact that I love you. After you take your shower and get ready, take the stack of envelopes I left for you by the front door. Open each one only at the time marked on the outside of the envelope. I'll be thinking about you as you open them. Have a fun day!
You should be having lunch right now. I wish I could be there with you. Remember when we were dating and...(enter a special memory). I've enclosed a piece of gum for when you are done with lunch. I can't wait to see you tonight!
So, you get the idea. Start small and build up with each hour so that he's READY to come home! Spray one of the last ones with your perfume, put on lipstick and kiss one, put pictures of you on your wedding day. When I did this for my husband I got a little creative and didn't hand write all of them. On some, I cut words out of magazines and pasted them on paper just to make it more fun.
My husband isn't a super romantic guy but he LOVED this. It made his day!
PS I got this idea from a book called Ways to Say I Love You.