can anyone tel me whats the best merchant for online store thanks

It depends very much on where you are located, which country and what your business is ?
Also I think ppl need to know what our monthly sales are (estimate) and also if you are looking for a e-wallet like solution or something like 2co.com or if you are looking for to become your own merchant account.

its an online gadget store. sales i dont no becaust i am new to online store and its my first online store

If it is a new business I would go with 2co.com to start with, once you have build your business and get some volume you can jump into your own Merchant Account with some of the ISO's you can find on google or maybe one of the guys which heavily post here.

how much it cost to have ur own merchant account

typically 10$ per month plus transaction fee based on total amount. You may also consider payquake.com, and cdgcommerce.com. Good luck!

What EXACTLY are you selling?
It really depends, certain merchant accounts wont even accept you if your selling BIG NAME products without Reseller License/some Authorization...some wont let you sell 3rd party/replica items.
Really depends on what your selling and where you are located.
Ive seen in a few other posts you plan on selling products overseas?? Could be a HUGE problem as well, some merchant accounts will not accept you if more than X% of your business is outside the USA.
For the most part merchant accounts are cheap, but price varies depending on what your looking for.

how does this payquake.com work? like what do i have to do to get started please explain

You probably get better answers by calling them directly. With payquake, there is no monthly fee, but $9 monthly minimum.
Where as cdgcommerce and authorize.net, you have to pay around $10 plus transaction fee. However cdg and authorize.net scores good reviews compared to payquake. Good luck!