Newbie question(s) about buying a replacement Battery for n610c, etc.

Hello. First post. And yes, I did a search and couldn't find
anything regarding my questions.

Question 1: I have an n610c and the battery is nearly dead (I
actually had two die - I bought it used with one new spare battery).
The original battery died a couple of years ago and the identical
battery died a week ago. I am in the market to buy one and yes, I
realize they are expensive. Was wondering if anyone would know the
best place to buy refurbished/off brand batteries for these laptops?
I have found genuine replacement batteries to cost upwards of $120 or
more. The off brand (non-OEM) are in the $45-$100 range. I did find
some on eBay - after shipping, etc. they cost about $50-$55. So...
any ideas on the best place to find these cheaper?

Question 2: Is there a way to renew these batteries? In other words,
seems such a waste to just toss these in the garbage when they are
dead. Was hoping there'd be a way to refurbish them.

Question 3: If there is a way, I'm sure some company, etc. is buying
the dead batteries to refurb them (I assume). If yes, who is?

Thanks in advance for your answers. Sincerely,
n610c-guy