I have a 1994 Ford Thunderbird with the standard head unit.
I know the car takes 5x7 and 6x8 it doesn't matter
on line I found these two sets of speakers for about $82 total
($46 for Polk db571)
($36 for Eclipse SE8375)
I might upgrade the head unit in time but since I am 17 that might be awhile.
I also whas thinking of putting the 3-way Eclipse in the front and the 2-way Polk in the back.
Links to a site that sell them(Not where Iam buying them from)
Polk Audio db571($45)
Pics of both: