With things like this, the fun part is buying them. Whether you actually use them or not is secondary, you know?
Literal
This-kind-of-thing [topic-は], buying [subj-が] fun [feminine-のよ]. Use or not-use [such-things-なんてのは], secondary [copula-なんだって].
こーゆーの is a very casual phonetic spelling of こういうの 'this kind of thing.' 二の次 'secondary / second priority' is a set noun. なんてのは is a dismissive nominalizer — 'trivial things like whether you use them.' なんだって combines the explanatory んだ with って (casual quotative/hearsay). A natural, lively feminine-speech sentence about shopping pleasure.