some thread sources with good selection and good prices are-
connecting threads
superior threads
atlanta thread company
sulky
metro embroidery
thread art
joannes, hobby lobby, michaels also carry large selections-
buy one or two spools/cones- try them out= if they work for you keep track of where you buy them so if you hate it you know not to buy it again- if it works great you can go get more colors.
some machines are quite (thread picky)
you need to find what works for you...a little at a time- don't invest alot all at once-just to find your machine will not sew with it.