Maybe sell it for the sP until you decide for sure if you want to make him a BR Endeavor? Because after you potion him you might just think, "Ugh I should have made him a BR ____ instead," ...
[flower=Emily]
Oh wow! Congratulations! I've gotten some map pieces and stuff, but a potion?! Now that's lucky!
I think that you'd probably be best of using the potion if you really want a BR pet... you can always do quests and things to make the money after all, right? And BR potions can get pricey if you wanted to buy it later on...
Get the pet. You can always get the money at another point in time. :)
I also think you should make your pet bloodred. First of all, a pet is something special while money is just money. And bloodred potions are a bit deflated lately, aren't they. So if you wanted to make him bloodred later, you'd have to pay more than you got for selling the potion.
You can always make money back, but pixelated pets are forever :P
Plus, the BR Endeavor looks so badass :o