How to to get the prices centered in the node:teaser with commerce price savings formatter?
Add this in your CSS:

table.commerce-price-savings-formatter-prices{
width: 100%;
}


Also, you can add:

.commerce-price-savings-formatter-price .price-amount{
display: block;
padding-top: 5px;
}


Prices looks much better with this.

If width:100% doesn't work try to use width:100% !important; because width is already defined in module's theme.

To remove line above price add this to your CSS:

table.commerce-price-savings-formatter-prices tbody{
border-top:0;
}


Also, if it doesn't work, use border-top:0 !important; instead border-top:0;

To minimize the space between prices add to CSS:

table.commerce-price-savings-formatter-prices-down{
margin: 0 auto;
width: 50%;
}


Important part here is width: 50%;, change this percent to see which space you want to have, the more percent is the more space will be between prices. Again, use !important if doesn't work.

You can also add this to your CSS to make prices look better (to make it equal at the bottom edge):

table.commerce-price-savings-formatter-prices-down tr td{
vertical-align: bottom;
} 


Don't forget to clear cache.