They're located at the very top underneath where you buy plasmid slots. That's at least 4 plasmid slots, since you start with 2 you'll need to buy at least 2 more. You should be able to purchase it at the second gatherers garden:) Upvote. The price does not change during the game. You can also only buy a maximum of twelve tonic slots throughout the game. You can buy either of two kinds of ability slots -- plasmid (special power) or tonic (passive ability) --that allow you to use many talents simultaneously. You can also only buy a maximum of twelve tonic slots throughout the. Plasmid Slots are purchased at Gatherer's Garden machines throughout Rapture for ADAM each. They're located at the very top underneath where you buy plasmid slots. If you don't. Click to expand then you are able to buy. Tonics are so varied that it's pretty much. Comprar los 3: $00$ Comprados juntos In Bioshock 2, you have numerous tonic slots/plasmid slots, etc. extra objectives and it took me at least 25 hours. . The 2nd area - Neptunes Bounty has a Gatherer's Garden where you can buy an extra plasmid slot.