Kingwill

Recently bought a signum and wanting to get the timing chain done. My question is that i had a quote of vauxhall for a main chain kit and gaskets @ £398 and a secondary chain @ £194 and £325 to fit both at the same time. Now i have not got that sort of money but i dont want to leave it too long and risk my investment. I have seen on various sites for full timing chain kits @ around the £75-£98 mark but no mention of main or secondary chains? Will buying this kit work? Are they not the real thing? I may be being stupid but im not a mechanic and dont understand from main chain and secondary and which one these kits are. As the kits seem genuine enough from alot of places? Any help from someone experienced would be great. thanks alot.