I heard both yes and no. In fact I read somewhere that Lou was actually suing Bud at the time of his death. Wonder if any of this is true?

Also next time you go to a 7-11 or any convience store/restaurant and put ice into your soda you can thank Lou Costello for that. He invented the machine that makes ice.
There is a short film of him and his invention that sometimes get shown on AMC of it.

No they didn't hate each other. At times they were upset or angry but I don't think ever hated one another. Lou always appreciated the way Bud was there for him when his baby died (in a drowning accident in 1944). Bud appreciated the fact that Lou looked out for him during his epileptic attacks. They were partners in business more than social friends. Bud did get genuinely upset about the business not being 50/50--as Lou got 60/40 of the take. Lou didn't like Bud's drinking especially towards the end when it caused problems with the act. That really was what broke the camels back and led to the breakup of the team. There is a picture of Bud at Lou's funeral looking very grieved indeed.

...it's just that they had slightly different interests, especially financial ones.
When they produced and starred in "JACK AND THE BEANSTALK" and "ABBOTT & COSTELLO MEET CAPTAIN KIDD" in 1952, it was decided that each of them would own the rights to one of those pictures. "JACK" was Lou's favorite project, so he got that, while Bud took "CAPTAIN KIDD". Unfortunately for Lou, his estate failed to renew the rights to that film after 1980, and is now widely available in the public domain. I don't know if Bud's family owns the rights to "CAPTAIN KIDD" anymore. I DO know that the boys' filmed TV series is STILL owned by the Costello heirs, and they make money every time it's on TV or bought on DVD and other home video software. I don't think Bud appreciated the fact that he had to work FOR Lou in those "classic" episodes and be his on-screen partner at the same time. And Lou tried to be a TV producer with George Raft's "I'M THE LAW" in 1953, but it was a one-season syndicated wonder- and "Cosman Productions" fell by the wayside.

I remember watching a tribute show with Seinfeld, Larry Charles and Larry David(I think i got the names right) other people at Bud Abbotts house and one of them said that whatever size pool Bud had Lou made his bigger and anything Bud had Lous was bigger or better.

I guess since Bud was always getting the better of Lou on the show Lou decided to get the better of Bud in life.
IMHO Bud Abbott was way to rough on Lou and they said that the slaps Lou got from Bud were actually real slaps which brings me to the question.......

Why didn't they have a sound effects device/maching like The 3 Stooges did ???