geesh i thought this would have already been compiled but any ways:
with the ever slim budgets we give our selves fro starting fish tanks, substrates can easily break the bank. heres a list of some that can be used in aquariums with good luck.

black diamond sand blasting grit 8$/50# bag.
*cat litter non sented or treated please so many choices prices could be 8$+/40#
Safe-t-sorb 8$/50# bag
Floramax 9$/15# bag or 10$ /12# bag (this is the black) *petsmart online pricing*
turface pro league (price not certain and varies sorry) details here:
oil-dri ~10$/20# bag
pool filter sand ~8$/50# bag
play sand ~4$/50# bag
"aquarium" sand/gravel ~20$/20# bag
eco-complete sand/gravel ~23$/20# bag (off sale)
seachem flourite ~20$/20# bag (off sale)
organic potting soil. varies.

sand that inert from the list:
black diamond
pool fitler/play sand
"aquarium" sand/gravel"
cat litter

might contain nutrients for plants:
cat litter (depends on what you buy)
turface pro league
organic potting soil

made for planted tank:
eco complete.
seachem flourite

please note that just because you use an inert substrate doesnt mean you cant plant. you might just need to use root tabs (depending on the plant)
also all aquarium substrates should be rinsed before adding them into a tank. some more than others.

*cat litter. this can be both inert and has some nutrients for plants. make sure you arent using anything that has been treated for scents or anything like that. flourite based cate litters can be cheap and great for plants (as good as flourite from seachem). do your research on what brand you use before you use it please*

hopes this helps every one with their choices in aquarium substrates.

BTW these are the more common ones ive come across from reading/using there are most likely more.