There are only 4 add on packs on Amazon, they do not add any game time to the account. Only the Starter pack and Premium pack actually add game time.
The job related packs are meant as addons for the Starter Pack really.
If you just want to sub use this
Every thing other than the implants (do not see on the market, do not remember if they can be sold) can be bought on the market ingame.
Subscriptions usually don't go on sale, as there's a near-permanent 30% off sale on the 1-year sub. Of course that mandates wanting a full year, and having that much $ upfront...
Occasionally Amazon will have a sale, but you can't rely on that usually.
If you buy a month from Amazon you don't need to cancel a subscription. https://www.amazon.com/Month-Subscription-Online-Instant-Access/dp/B00GDHD3LW I know it says subscription in it's name but it's just a 1 month chunk.
You can buy a 6 month sub on Amazon and have it linked to your account. http://www.amazon.com/Month-Subscription-Online-Instant-Access/dp/B00GDHD3LW/ref=sr_1_1?ie=UTF8&qid=1460561869&sr=8-1&keywords=EVE+sub in the us.
Don't use steam.
Amazon is currently having a 10% off promotion for game time.