I started with the 10" Silicone Loaf Mold from BrambleBerry. I liked that size of bar, so when it came time to upscale, I went with the 5lb Basic Mold from Nurture Soap...it's a rectangle wooden box with silicone liner. When my BIL saw it, he made me six boxes and I just bought the liners.
Now in between BrambleBerry and Nurture Soap, I did trying lining a mold I got from Hobby Lobby and decided I didn't like having to line my molds.
NS does make a Premium 5lb Mold...one of the sides comes off and it comes with a clear lid. I don't make fancy tops on my soap so I have no need to remove the side of the mold. I just turn it upside down and push on the holes in the bottom of the mold and it pops out. I then clean the liner, return it to the box and put the cardboard insert back in. As for a lid, we have a company in the neighborhood that makes custom wooden crates and sets their 'scrap' wood outside for folks to pick up. I just found a few long pieces and cut them up.
I did consider going with slab molds, but my sales don't [yet] warrant making 25lbs of any one soap at the present time.