What do the voltage and current labels on a relay signify?
That's the maximum voltage and current on the switch (=load contacts) side. The current is for a resistive load. You also need to worry about the coil side parameters.

Also you should consider buying stuff where photo and web page agree. The latter says 12V, although looking at the very fuzzy picture they have, that seems to be coil voltage. Never mind that there noting resembling a datasheet for that relay. You get what you pay for.

A guide like this or this (which is more detailed) is worth reading before buying relays.