Well, the most common swap for a 90-93 Accord is the H-series. Here's a list of motors that can fit into 90-93 Accord.
H-Series List:
1. H22a1 ( year 92'-96' Prelude ) / OBD1 - Price: $1,900 to $2,500
( Highly Recommended )
2. H22a2 ( year 96'-01' Prelude ) / OBD2 - Price: $2,200 to $2,800
3. H22a - Type S ( year 97' + Prelude ) / OBD2 - Price: $3,000 to $3,699
4. H23a ( year 96' + Prelude ) / OBD2 - Price: $2,500 to $3,000
F-Series List:
1. F20b ( Accord Euro-R ) / OBD2 - Price: $3,000 - $+
Well, prices on the motors can vary from distributor to distributor. Usually, H22a1 can run you $1,900 to $2,500 with or without shipping. That should come with a longblock, intake manifold, exhaust manifold, transmission, axles, shift-linkage, and ECU. LSD is extra. Newer the motor, the more it will cost you. Here are some online distributors: Hmotorsonline.com, Totaljdm.com, JHPUSA.com, and Noyanusa.com.
As for B-Series motors, they can not be swap into 90-93 Accord. If they could, it would be quite diffcult and costly. But, anything is possible if you have mad money to throw around.
Also, I think 90-93 Accord is an OBD0. So, you may need to a get an ECU jumper to convert your OBD0 to an OBD1.
Hopefully I was helpful to your research.
Note: Don't hold to the prices, but those are some of prices I've seen when I did my research on a motor for my car. Also, some of the information I have provide may not be accurate. Please don't haste to correct me.