There are at least three of them gathered together in one scene.
So yeah, multiple dreadnought+ sized vessels. Capable of intergalactic travel.
Built with "resources"?
Its possible a lot of the richest folks in the galaxy pooled their resources together to build the ships to go to Andromeda. Why? For bragging rights. For the adventure. Because they can. All that are going are volunteers. Each species sends of few units of soldiers from their military to provide security and any other help that may be needed.
I still believe the ships leave before the events of ME3. Did anyone know about the project? Sure. Most likey didn't give it much thought once the reapers showed up.
If they leave after the events of ME3, I would be curious how long after. I would also be curious what explanation Bioware has for what ending they chose or more than likely the game will give some vague explanation.