Coming down I-49 to Springfield, MO and hitting I-44 westbound, I-44 is Will Rogers Turnpike (toll) from the OK state line to Tulsa. If you continue on I-44 to Oklahoma City it is the Turner Turnpike (again toll). You can calculate the tolls in the link above.
If you take I-35 from Kansas City to Wichita, KS and on down to OKC, it is the
Kansas Turnpike (toll thru Kansas).
Either way it will cost you about $25. For speed, peace of mind, and reasonably good highway it is worth it to me if I am simply trying to get from point A to point B as quick as possible.