Hello, I Am A 79 Year Old Male. I Have

Hello, I am a 79 year old male. I have had bph for many years, probably close to 25 years. One year ago I was diagnosed with prostate cancer. I took hormone therapy (Eligard) for 1 year and had approximately 45 radiation treatments. My psa went from a high of 9 to .016 recently.
I am presently taking oxybutynin chloride er (10 mg) and tamsulosin (.4 mg) daily. My urine flow is good and the urgency is quite good as well.

Next year my oxybutynin chloride er will cost me quite a bit more. My drug insurance company made it a tier 3 drug. It is tier 2 this year.

Is there another drug that I can use to provide the same effect as oxybutynin but with a lower cost?