Trailer registration is only $10 per year here in NY, atleast thats all I pay for mine.
Ive never gotten it inspected. Theres no point in doing it because the sticker doesnt go on the trailer itself and nobody ever checks for inspections on trailers. If for some unlikely reason I get stopped for it Ill just say I left the sticker in my other car. $15 NYS DMV is not getting from me.