Cost to be paid when hosting Republican internet pest (5)
I believe the answer is:
troll
'internet pest' is the definition.
(abusive or irritating internet user)
'cost to be paid when hosting republican' is the wordplay.
I cannot really see how this works, but
'republican' could be 'r' (abbreviation) and 'r' is found within the answer.
'cost' could be 'toll' (toll is a kind of cost) and 'toll' is found within the remaining letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for troll that I've seen before include "Fish by drawing bait along in the water" , "Ugly character from Norse legend" , "Fish - gnome - sing" , "cave dweller" , "Scandinavian dwarf or giant" .)