I use Seachem's fert line for dosing actually. I use their Aquavitro line (which is only available through LFS btw, not online), and have had pretty good results with it. It's HIGHLY concentrated stuff, and I've been dosing 2 tanks, and only my micro bottle and iron bottle are starting to run low, and I bought the stuff in March
Also Seachem's Premier water conditioner, which I just picked up yesterday, works at the same concentration as prime, but also adds in potassium which is awesome. I use Envy (Micros), Propel (Iron), Synthesis (nitrogen), and Activate (Phosphorous and Potassium). For my 40 gal I follow their dosing guidelines, and I've gotten awesome results. They may be more expensive (It's 10 dollars for a bottle) then dry dosing, it's very easy, but at the same time it's not overly expensive either.
Aquavitro website: http://www.aquavitro.com/products/plant.html
Also I used the Ista disposable CO2 cartridge system, and it got very expensive, very fast. I was going through one cartridge every 3 days, and that was conservative use. I picked up a nice regulator set up for $120 at my local hydroponics store that has a great needle valve and solenoid, and then put down a $150 deposit on a 20lb tank that costs 6.99 to get exchanged for a full one. One of those cartridges was 10 dollars, so for a month's worth of CO2 it ended up costing me $100, and it wasn't even enough CO2 for my tank.... The only good thing that came out of the kit was the diffuser/bubble counter combo.