Can I drop objects on spaces anytime I want? Can I discard objects if I don't want to keep them or do I have to drop them to space? Can I discard spell if I don't want to keep it?

These are all basic questions that are directly answered in the basic Rulebook.

This time, I'll do the hard job for you; next time you do it by yourself.

Tuomas85 said:

Ditching Followers and Objects (page 16)
A character may ditch any of his Followers or Objects at any
time by leaving them faceup in the space he occupies. If a
character ditches any Followers or Objects, he cannot take
them back during the same turn.

Tuomas85 said:

Object Carrying Limits (page 12)
No character may have more than four Objects unless he has
a Mule.
Any character acquiring more than four Objects must decide
which to keep. The remainder are immediately placed faceup
on the character’s space.

You use the word "discard" but please note that you cannot "discard" Objects on the discard pile, you can only "ditch" them on the space. This can be done by your own will (see Ditching Followers and Objects" or because you exceed the limit.

Tuomas85 said:

(page 12, just below the box "Example of Spell Limit")

If at any time a character has more Spells than his Craft
allows, surplus Spells must immediately be placed on the
Spell Card discard pile; they cannot be cast. The character’s
player chooses which Spells to discard. Spells cannot be
discarded unless the character has more Spells than his Craft
permits, however. The only other way to get rid of a Spell is to
cast it!

I know you can not have more than your spell limit but if you have 3 spells and you encounter a space that allows you to gain a spell.

Do you get to draw one than discard one of your choice or not draw one at all?

I have played it that you simply dont draw one and haven't seen a rule that says you cannot draw a spell if you are at your spell limit.

Also if you have four objects and you draw a bag of gold, do you have to drop a object to recieve it?

Since you would have 5 objects picking up the bag of gold.

If you gain a spell and you already have your maximum number of spells then no you can't draw a new spell, unless you can cast one your spell before, this spell must be a spell that can be cast at anytime though.

No, gold doesn't count towards your object capacity limit.

BlueHawks206 said:

usually a card that grants you the option to draw a spell card has the writing "if your craft allows it".

this makes it impossible to draw spells beyond your craft limit.

This could suggest a neat 'house rule' where if you are at your spell limit and may draw an additional new spell, you can then choose between your existing spells and the newly drawn spell as to which one you will discard… a good way to get rid of really annoying spells…

No…?

I know at least one characteror object allows you to draw a spell, discard it if you choose, and draw another spell, which must be accepted, but only if you don't have your maximum spells you can carry.

^ I believe the Philosopher can do that automatically. Also the Verdant Witch follower from the Dragon expansion lets you draw two spells any time you are given the opportunity to draw a spell, and then you choose which one you want to keep.

Runeblade said:

You certainly could do such a house rule, if being stuck with spells is something that your group has found to be an issue.

Personally I like the fact that you can't just discard spells you don't have a use for, since it provides a small limiting factor to those characters who always have a spell or who are allowed to draw spells every turn. Forcing them to find a valid way to use those spells, or seek out one of the spaces/cards that let you exchange spells for gold/dragon scales/etc., keeps those types of characters from just constantly cycling spells until they get the specific ones they are looking to win the game with.