Walmart.com online has the real deal Denso's and the cheapest I could find anywhere,and I shopped em hard.

 

Denso, which are OEM, cost only few bucks more than aftermarket ones but they come with the OEM plug so there is no soldiering involved. You should be able to find them on rockauto. I'd go with Denso. (that's what I have on mine and they are perfect)
To replace front ones is not terribly hard, although you have to lift the carpet inside your car too. The biggest problem is usually that it is hard to unscrew them; my friend who helped me the first time used a plumber's wrench for good grip and it worked.
Make sure you put an anti-sieze compound on the threads of the new O2 sensors so that next time it is easy to take them off! This is the one I used (and it's great, works like a charm on squealing brakes): 3M 08945 Copper Anti Seize Brake Lube

 

The Denso/s will come with a small packet of copper antisieze. It only requires a small dab to provide a sufficient coating on the threads. Have seen far to many You Tube videos where the installers slather it up like spreading butter on bread. Toyota seems to put them in dry in the cars I've done.

 

Plug and play,whats not to like? Prices are plenty reasonable too.

 

True on both accounts! I actually bought that 3M stuff for my breaks and I swear by it. But, yes, Toyota uses none, and they are a PITA to remove.