First off, two good places to buy KR808D-1 cartos are vapor4life.com and vapornine.com.
At V4L, get the "cool carto" blanks.
At vapornine, get the "turbo" blank cartomizers.
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As for juices, I'd also recommend tastyvapor.us
If you're happy vaping at 16mg with a 50/50 PG-VG blend, and order one of the "weekly special" flavors, you can get the equivalent of six 30mL bottles for $35, or $5.83 per 30mL bottle.
For example:
1oz of Almond Horn @ 48mg, 10% VG ... $10
1oz of Almond Horn @ 48mg, 10% VG ... $10
4oz Doubler of Almond Horn @ 70% VG ... $15
= 6oz (180mL) @ 16mg, 50% VG ... $35
OR...
1oz of Coconut Cream Pie @ 48mg, 10% VG ... $10
1oz of Coconut Cream Pie @ 48mg, 10% VG ... $10
4oz Doubler of German Chocolate Cake @ 70% VG ... $15
= 6oz (180mL) @ 16mg, 50% VG ... $35
At regular price, it's $7.50 per bottle.
Get three flavors (you'll have a grand total of 540mL), and -- having passed the $100 discount threshold -- you'll get 10% off your order. Then trade with other Tastyvapor fanatics here on the forum so you can try their other flavors. I've never tried it, but I've heard that TV juices are highly coveted in the trading market. One might say it's a very "liquid" market.
Good luck.