There is a new member section of the forum for post like this, but no worries. Welcome to the forum.
In terms of your questions, the stock sport rims are fairly high quality. They retail around $900 apiece (although they can often be found new for around $500 apiece). Most people replace them with lower quality wheels
Should you sell your sport wheels?
That's up to you. Is an extra set of wheels useful to you? Do you like/hate them?
How much money can you get?
In the past... I typically bought good condition sport wheels for around $800 with tires and sold similar condition sport wheels for around $1000 without tires. They are market dependent to a degree.
Should you save for another set of wheels?
Again, your decision. Do you have another set of wheels in mind? That should probably be a key factor.