Before going mail order for self pay, get a price for the med from Costco or Sam's pharmacy. When I thought I was going to take a med that my insurance would not pay for, I priced on-line pharmacies (recognizable name, some track record) and Costco came out as cheap or cheaper.
A Consumer Reports analysis of brand name meds, not the inexpensive generics, showed Costco to be cheaper. I also think that many Costco locations allow for using the pharmacy even if you are not a member, as does costco.com.
For my insurance long term meds, we have been using Medco or the designated mail order pharmacy for over 20 yrs with no problems. Occasional communication issues have always been favorably resolved by phone or email.