The DNA store is a part of the in-game main menu where you can buy DNA via Robux and see your current DNA. After every 12 hours, you can get a 'daily bonus' of 100 DNA. This allows up to an additional 200 DNA a day, so it is recommended you collect the bonus whenever you can. The store is available on all maps, including the trading map, making it useful as a expensive "Top-up" on DNA.
DNA is purchasable using ROBUX.
|ROBUX cost||DNA||Bonus DNA||Total DNA||DNA per ROBUCK|
|4 ROBUX||10 DNA||N/A||10 DNA||2.5 DPR|
|20 ROBUX||50 DNA||10 DNA||60 DNA||3 DPR|
|40 ROBUX||100 DNA||25 DNA||125 DNA||3.125 DPR|
|200 ROBUX||500 DNA||150 DNA||650 DNA||3.25 DPR|
|400 ROBUX||1000 DNA||350 DNA||1350 DNA||3.375 DPR|
|800 ROBUX||2000 DNA||800 DNA||2800 DNA||3.5 DPR|
|2000 ROBUX||5000 DNA||2500 DNA||7500 DNA||3.75 DPR|
|4000 ROBUX||10000 DNA||7250 DNA||17250 DNA||4.3125 DPR|
Considering that 1 ROBUCK is essentially $0.01 USD, 17250 for 4000 ROBUX means the maximum efficiency will get you 431 DNA for every dollar you spend. Likewise, the minimum efficiency at 10 for 4 ROBUX gets you only 250 DNA for every dollar you spend. Because of this, many players recommend against buying DNA with Robux. As you can easily get that much DNA with just farming a 25 Day Old Barosaurus for a couple minutes.
You can also spend ROBUX to get DNA with the Party Box Gift by pressing the P key, which costs 40 Robux. However, be reminded that this gives everyone but you free DNA.