Revanke's Journal

Hi, my name is Revanke, and I'm 37 years old. I underwent Mitral Valve replacement surgery in February. The recovery seems to be going well other than for slight stomach irritation and irregularities at times which im guessing is due to the post op medication which i have been taking for the last 3 months.
I have been asked to take Warfarin to manage the thinning of blood, and it was monitored weekly through a PT/INR test which now is done every 2 weeks.
I was told that a home test machine is an option to check the INR levels and is there any particular machine/ brand that could be recommended? Also, how much would such a home test machine cost?