The honest value of a paid party pack is not the theme. It is the hour or two of matching fonts, colors and sizes across a dozen items that you did not have to do yourself.
A listing that says "50 files" may include the same banner letter repeated as separate files for each letter of a name. Look for a description of the distinct pieces — invitations, a banner, toppers, a sign, a game — rather than a large file count inflated by repeats of the same handful of designs.
A cupcake topper needs a specific small size; a banner needs to fit standard letter or A4 paper without you resizing it. If the listing does not state dimensions for each piece, you are relying on a thumbnail being to scale, which it usually is not.
Some packs commit to a theme throughout — matching icons, matching border details, a consistent motif; others are a generic template recolored to match a theme name in the title. Look closely at whether the illustrations relate to the theme or only the color palette does.
A pack where a name and age can be typed directly into a PDF or template, rather than requiring separate design software, is doing real work for a buyer who does not use design tools. Check specifically whether text is described as editable, and in what program.
Our own party pack for a specific occasion is ours, and it is themed throughout rather than a generic pack with a color swap; we state plainly which files are editable and which are fixed-size prints. It covers one occasion, not a general template for any theme.
There is no fixed number. Look for distinct pieces rather than a large file count made up of repeated letters or duplicated designs.
Usually not for a text-fillable PDF, which most free PDF readers can handle. A pack requiring design software like a browser-based design tool will say so.
Look for stated dimensions in the listing, and print one test page at actual size before printing the whole pack, particularly for anything that needs to fit a specific cup or plate.
Part of our guide to Buying guides: how printables work.