"I am buying clothes."
Translation:Táim ag ceannach éadaí.
No - cuid is used with a mass noun after a possessive adjective. In my experience, cuid isn't used on it's own to say "some" - you can say cuid mhór tó say "a lot (of)" or cuid acu to say "some of them" , but it would be roinnt éadaigh if you wanted to explicitly say "some clothes".
A general comment on one part of the tips and notes to this skill - see below. The examples given with it are incorrect, in fact they contradict the point being made.
"However, if the verbal noun clause needs to be followed by a prepositional phrase in order for it to make complete sense, then the genitive case is not used. Táimid ag caitheamh seachtaine i Londain We are spending a week in London Táim ag lorg oibre sa Rialtas I am looking for work in the Government"
The examples should be with "seachtain" instead of "seachtaine" and "obair" instead of "oibre".