People already have probably seen this deal on the prime video site, for $2.99USD/mo you get prime video + a free twitch prime sub each month(4.99 value) for 6 months then $5.99USD, can end it at any time.
My trial had run out, today there is a trial offer via twitch(prime loot dropdown box) that allowed me to begin a new 6 month discount at the low price again. Might be worth checking out if you are in the same situation.
no idea, I use uBlock Origin and don't see any
You will still get the video ads even with Twitch Prime. Officially, you need to subscribe to the more expensive Twitch Turbo to avoid ads for all channels. Also, most channels have ad-free viewing for subscribers (the default) so if you subscribe you won't get them for that channel. With Twitch Prime you get one free subscription per month. The streamer still gets their standard US$4.99 cut. While there are ways around the ads, some suggest you should only use them if you subscribe to the streamer otherwise they're missing out on their share of the revenue from ads, as tiny as it may be compared to subscriptions and sponsorships. Of course if the streamer says they don't care then you're all good.
See
https://blog.twitch.tv/en/2018/08/20/changes-to-twitch-prime…
and
https://help.twitch.tv/s/article/twitch-turbo-guide
and
https://www.twitch.tv/turbo
and
https://help.twitch.tv/s/article/ads-experience-updates
and
https://help.twitch.tv/s/article/partner-settings-guide
Do you still get ads on twitch ?