depends on which type of top coat (varnish) you prefer.
some people swear by matte varnish, others swear by gloss.
but the best tip i can give, if you use acrylic paints is not to buy the specialist ones in little pots whenever possable.
i used to do that, and i spent a lot of money back in the '80s on them.
then i discovered craft shops did large bottles (compared to the tiny pots) of not only paint, but varnish and effects (pearl mix is realy wonderfull. fine glitter and glow in the dark ect have uses too)that can help you make some fantastic set pieces
(the glitter, if the aurora type, can be used to great effect in making frost, ice and slime effects for multiple time settings)
if you still prefer the small pots, then i reccomend you keep your empties (for refilling) and just buy your main primarys (red/blue/green/yellow) and the bases you use most (usualy white and black, but everyone uses those two more anyway for lightening and darkening, so you allways need more) along with a large matte and gloss varnish. its much cheaper if you grab those from craft shops in reasonable size bottles becasue you can go through so much if you are (like me lol) a double coater (2 coats of varnish to make sure they dont chip lol)
i havent bought any little pots for ages now, but whenever a craft shop has a sale, i buy those main colours, and any varnish i can, and that keeps me going. (and they often arent selling them as paints, but as just general craft acrylics, so are often cheaper)
you can still grab the spcial case ones tho, if you need them for highly specific coloursets and stuff. it can be realy hard to mix the same shade if you have a large set to cover. but the varnish from the craft shops is a bit of a must (for me at least lol)