You can get injection mixes in a lot of different flavors at Gander Mountain. They run less than $5.00 / bottle there. They have peanut oil too....good price in comparison to grocery stores. I have also used melted butter with a mix of seasonings from the cupboard and had tasty success.
As far as storage, you can pump it back into the original container after it cools. A D cell pump and filter kit can be had for around $12.00. If you use the filter kit, you can really extend the life of that expensive peanut oil.