> 
> Some of them would say I'm half a duck   
> 
>  I may be used if you want to try your luck   
> 
>  I inspired your sweetest dreams, will say the most accurate   
> 
>  But for only 15 of them, it was worth a rate   
> 
>  Some of them tend to collect me   
> 
>  Even if I'm usually just worth a few penny   
> 
> 
> 
> 

**Ilia L** found the good answer, but I need a good explanation for the 'rate-riming' lines.   

 So here is a hint

> 
>  line 3 refers to a famous song from the 80s, maybe I should have added a tag, but it's only my second puzzle on this site so I don't really know how it works
> 
> 
>