I jumped right in and bought a Blu Premium starter kit and a bunch of cartomizers before I had done any reading or learning about vaping and before I discovered this forum. If I were starting over, I take the money I've spent and set myself up with a more advanced kit. However, I'm trying to make the best of my decision, and I'm using what I've already bought before spending more to upgrade. Fortunately, I haven't had any of the problems with Blu that others have run into. Everything is working as advertised so it's OK. And I'm enjoying it. On the other hand, every time I change a battery and/or cart part way through the day I'm reminded that there's a better setup waiting for me. Also, going through a couple of carts a day costs about the same as a pack of analogs around here. So, Blu is definitely not the most economical way to vape.
I started with that same Blu kit, and it worked well for me, too. It let me know that the e cigarette concept might actually allow me to stop smoking, so I am very grateful for that. Like you, I quickly realized that buying the cartridges would get pretty expensive, as I had been smoking up to a couple of packs a day of cigarettes.
I also didn't like the short battery life since I was a heavy user. I felt like I spent all my time plugging and unplugging the batteries to be sure they were charged up and ready.
If you decide to upgrade, here is what I ordered to replace the Blu. It's a Kanger Evod starter kit, and comes with everything you need except the juice. You get two batteries, two toppers and a charger. The ego batteries are not huge, about the size of a Sharpie marker when you have the clearomizer on them. I didn't have any trouble adjusting to the size, compared to the Blu's.
This is a reliable vendor, and if you use the code ECF at checkout, you get 10% off, making the kit about $30, which I think is a really good price:
Kanger EVOD eGo Full Kit - Vaping Me