If you don't already make your own hummingbird and oriole nectar, you should. It's cheap and easy and attracts the birds just as well as the store bought stuff.
You will need white sugar and water. Combine 4 parts water to 1 part sugar. Boil. Then let it cool and fill your feeders! Any excess can be stored in the fridge. You don't need to add red food coloring either. As long as there is red on the feeder itself, hummingbirds will come!
I use the same nectar recipe for my orange oriole feeder. I've read, though, that the oriole nectar should be 6 parts water to 1 part sugar. I don't think it matters, since orioles will try to feed from hummingbird feeders too. It's just easier for me to use the same nectar.
Another cheap trick for attracting orioles, is to put out some grape jelly. I have a flat bird feeder stand and I set a plate on top of it with a couple spoonfuls of grape jelly. Robins and cardinals also seem to like it!
It's probably a little early for hummingbird feeders, but I plan to put out my oriole feeder this weekend. I'm not really sure what their migration schedule is, but even if it's too soon I figure it can't hurt!
Happy bird watching!