I am looking for an Android phone with 3G and dual SIM.
If you have no problem with MediaTek processor based phones then Xolo Q1000 would be good.
If yes,then Sony Xperia M would be better option for you.
galaxy s duos is good right now, at INR 9.5k.
else, the micromax canvases are ok, if you are not too much bent on build quality and after sales service, and brand name.
LG OPTIMUS L5
I own a Samsung Galaxy Ace Duos S6802 and I bought it specifically because it has dual sim and 3G. The 3G is NOT simultaneous, so you have to choose which sim you want to do your 3G on.
Its running Android 2.3 which is old and the phone is fairly underpowered so its not fast and if youre used to an iPhone or Samsung Galaxy S4 or something like that, it will not be pleasant to use all the time. I mainly use it for when I travel. I can pop in a local prepaid sim, turn on the 3G sharing and all my other devices (Samsung Galaxy S4, iPad, etc) can get on the internet via the 3G hot spot. Battery life when using the hot spot feature is only 3-4 hours, but its enough for me when Im out and about and away from my free wifi.
I have a BLU Studio 5.3 and it supports 2G and 3G and has dual sim. I bought 2 sim cards and took it to the mall to ask some questions. I use AT&T. But....they told me that AT&T does not support dual sim cards.
"Best" is a subjective term. Personally, I had a ZTE Racer (*very* cheap) and it was OK, except for the very small screen. I've just bought a Chinese TTsims N9770 (5.1" screen) and even tough it's cheap, I'm happy with it, but not sure others would be.
The new Moto (lauchned in the US only at this stage) is apparently quite good, but I'm not sure that the $199 price point entitles it to be called "cheap".
In short, decide on your price point, decide what features are really important to you (screen size, durability, design, dual SIM, whatever) and then search, or ask again!
You can search on Google and find a lot of results...
Anyway, if you check this link, some of the samsung mobiles are with an android system and with dual sim: