What is your goal with this cycle? Gain mass, loss weight, getting ready for competition, just feeling and looking better, increase sex drive?
With Anavar, unless you get yours through an actual doctors script and an actual pharmacy like Rite Aid, I don't care what kind of reputation a supplier has you need to buy a roid test kit and test the quality. This is the site that has the tests I prefer to use: https://roidtest.com/
I can't speak for the suppliers listed on this site as I did not use them. The brand or lab my 51 year old wife is using is Maxtreme and it tested good and she has seen good results without sides. Various distributors will carry this brand. Make sure to get the 10 mg pills and not the 40 mg as your max daily dose will be 10 mg broken into two doses of 5 mg each. Really hard to cut a 40 mg pill down to those sizes.
If someone tells you to take 2.5 mg a day, don't listen to them that is barely enough to replace your natural testosterone. Minimum daily does is 5 mg. I would do 5 mg for a week and watch for issues, if none come up jump to 10 mg in 2 doses 12 hours apart of 5 mg throughout the day. After that in all new cycles you can just start at 10 mg a day. If you have no issues at 10 mg some women depending on their goal go up to 15 mg or 20 mg a day, but you are definitely increasing the risk of sides doing that.
What to take with it will all depend on your goals. Once you let us know those goals and what kind of workout routine you plan on doing we can make recommendations, but Anavar by itself will do some amazing things when run 4 weeks on 4 weeks off or 6 weeks on 6 weeks off.
On a side note, Anavar is not a magic pill that will do all the work itself, you still need to push hard in the gym and work harder in the kitchen.