Last time I bought solder paste, I just ordered from Amazon. I usually order from Howard Electronics...
https://www.amazon.com/gp/product/B017RSZFQQI have a hot air tool but I have never actually used it. I guess I just don't do much repair work.
For new construction, I use solder paste and a hot plate or modified toaster oven. Both work well.
I also simply apply paste to both pads of a component and position it. Holding it with tweezers, I just use a soldering iron to heat and flow the solder.
For drag soldering, I use flux. Turns out that link above contains a 'kit' part way down the page. It adds flux and solder wick.
Considering the cost of the PCB along with the components, I can't get too concerned about the cost of solder paste. It's insignificant in the overall scheme of things.