Hi Daniel,
welcome to this forum!
First of all, although gannonce is not actively developed (it was developed before gchange existed as a prototype and to have some site to post offers while waiting for gchange to come up), gchange is alive and kicking as you can see here: Ğchange · GitHub
Etrillum has been offering Ğ1 as a payment system for 2 years now. In fact I was its first customer. 
Since then, other businesses are also selling fruit and vegetables in Ğ1 as well and a variety of things.
There is a form of block explorer (although a little different than what you are used to) here g1.duniter.fr which also serves as a wallet. You can either use the website for plain wallets but for a member account you should never use it, download and install the standalone version instead (desktop, Android…).
There is a paper wallet here: GitHub - Tortue95/Duniter_Paper_Wallet: Paper Wallet for Duniter cryptocurrency
I’m not sure what you mean by this. We don’t use the totally non-free currency called BTC here. As for how much 1 Ğ1 is worth, that’s entirely up to you. Come up with a price and see if people are ready to pay you that much for what you are offering - or if they are actually rushing to get your services at that ridiculously low price. 
There is no official exchange rate.