Master and clear spheres

I've heard a lot about these spheres, I know what they do but I dont know where to get them. Does anyone here know how to get them. By the way I've learned some helpful hints for people that need money or spheres that are awesome.

Money- buy armor from kilika. Steal things like lightning/electro marbles,candles of life, or anything else and make the armor lightning proof or what ever. It also helps if you have stamina tonic cause that'll make the armor have + Hp 30%

Warp/friend/blkmag/skill/whtmag/or most good spheres can be obtained easier than most people think. Make a lot of money and go bribe something for a LOT of money. I bribed a cactuar once for 1,000,000 and got 45 warp sheres. It lets you go anywhere on the sphere grid!! Normally these spheres only sow up in chests but with this method, you can have the sphere grid completed earlier.

Two words - monster arena.
Clear Sphere can be bought from the owner once you beat Ultima Buster
Master Spheres are the reward for unlocking Nemesis.

Also, to complete the sphere grid:
Fight One-Eye until he drops weapons with 3xAP and 2 slots
Customise 3xOD and OD->AP to said weapon.
Now, get three characters with this arrangement. Put your character who's killed the most fiends (e.g. Tidus) on stoic and the other two on comrade. (Auto-Haste for Tidus and Auto-Phoenix on one of the others also helps). Fight Don Tonberry, and have Tidus attack, and the others defend/revive. When DT no longer uses Karma, kill him or flee and you should gain MASSIVE levels. Rinse and repeat.

i also believe that you can get them whilst doing the omega rurins side quest.

Yeah, but only if you go through the entire cavern and never once touch the save sphere after you open the first chest, good luck if it's your first time! But it's good to know about the cactuar trick, I have 10 million gil, so a few wont harm.