==== Non-retail items ====
Oil: $0.20
CPU: $410-$450
STEEL: $17-$20
GLASS: $65
RUBBER: $17
PLASTIC: $1.20-$2
Furniture: $1.5k-$3k
GAS ENGINE: $10.3k-11k
Research Chemical: $150-$200
Energy: $12-$13
Energy+: $50-$70
==== Retail Items ====
Cars: $30k
Cars+: $100k
Drugs: $700-$750
Drugs+: $2k-$2.5k
:laptop: Laptops: $3k:laptop: Laptops+: $11k
If nobody else is selling, supply and demand should tell you to sell for more. Likewise, a massively overproduced item is NOT worth selling for the prices above. This ranges a span of about 20% higher or lower.