Subscription products like these usually have little or no value, but depending on the specific issues involved, there might be some value to a topical collector; there are a few wildlife sets from the 1970s/1980s that have a premium today.
The 1983 Burundi wildlife sets, for example, can be flipped on eBay
for a little money. These actually aren't even all that scarce, they're just hyped, maybe by some Afinsa-type scheme. They have a ridiculously high CV, though: around $1000 per set. Actually scarce stamps from Burundi usually sell for under $10, so figure the odds; there just aren't that many Burundi collectors out there. You can get a lot more for that 1983 issue on eBay
than most Burundi stamps, though, so somebody out there is paying for them.
Are your sheets unused or cancelled? That would be the first thing to know. Pictures of what you've got would tell me a lot more!