Best Whitening Lotion Please!

Since we moved here in Bulacan I noticed that my skin's getting darker and darker. I wasn't at my whitest back in Pasig, but here, it just seems like hell seeing my arms having different skin tones. My left arm is much lighter compared to my right arm. My legs literally has a line between dark and whiter complexion. I'm thinking it's probably because Jeff and I love to travel a lot without putting a sunblock before leaving the house.
Now, this is bothering me so much as it doesn't look normal. I would've wanted to put a whitening lotion, but with all the products in the market I'm not sure which to use and which to avoid. I don't want to waste money buying and trying all of them.
I'm currently using a Skin Firming Moisturiser from Nivea, Jeff's uncle from Austrilia bought a huge bottle for me. But I think I would need a different lotion to start my whitening goal. Please help me find the best, value for my money (if possible a little inexpensive) and promises a fast solution to my dark skin problems. Help!