You can have each child decorate a square of fabric and sew it together in a quilt. Or if you don't sew, you can use fleece squares and cut the ends of each square into small strips and tie them all together to form the quilt. We have done this numerous times and the parent always loves it.
How about having each child tell you their favorite activity that the room parent was involved with and then create a wordle with their memories. It wouldn't cost anything but the price of the frame and it wouldn't take much time, just interviewing the kids and typing them in. There are two websites you can use to create them, www.wordle.net and www.tagxedo.com. The first site just make random shapes but the second site lets you chose a shape. They are super cute, unique and so reasonable.
Some of my very favorite gifts were fairly inexpensive photo creations. Take a class photo with some kids holding up letter cards that spell out thank you. Go online to places that sell photo gifts (watch for sales, like around holidays or deals through Groupon) and create a tote bag or apron that all the kids can then sign in permanent magic marker.
How about an apron or shirt with the kids handprint? Use the kids hand print to create flowers and adding the words "Thank you for helping us grow!" It is usually used for teachers but if this is a very involved room parent it counts as someone that has seen and helped them grow. Or just adding the words "You deserve a high five for all your help".
I liked the handprint wreath design. In the past I have gone to a craft store and got a plain canvas type apron and traced one hand from all the kids in the class on it then let them color it in with their name and fav color. or you can ask thenm to give you a fav color and color it in. The teacher we gave it too loved it and the next year we auctioned one similar off for over $100. Hope that helps
