A day doesn't pass where we don't see a buyer complaining on the discussion boards about inflated shipping costs on eBay.

First, if shipping is not stated clearly in the auction, do not bid, until you have asked for & received a shipping quote from the seller.  Most sellers are honest, but there are those who will take advantage of a buyer.  But if you don't ask first, you have no recourse for (& won't get much sympathy) after the fact.  This also goes for combined shipping.  If  combined shipping is mentioned, but not clarified, always ask before bidding.  And if you see an item you really want & shipping cost seems high or you prefer a different shipping method, once again, ask before bidding.  Once you bid, you have agreed to the seller's terms.  Just as you do not want a seller to change the terms of the sale after the auction ends, do not expect the seller  to accommodate changes after the sale.

Why are many sellers charging such high shipping costs?  Simple answer - To avoid eBay fees.

Example:
A seller selling an item for 99 cents + $12.00 shipping pays eBay a total of 25 cents for listing & final value fees. Vs another seller selling the same item for $7.99 + $5.00 shipping who pays 77 cents for listing + final value fee. Seller with the inflated shipping nets an additional 52 cents.

My not sound like alot but it can add up in a month's time. Plus the seller avoiding the fees will have their listing show up first in a price search. In addition it hurts all sellers because eBay has gotten the reputation for rip-off shipping costs which discourages new buyers. If buyers want a site full of nothing but 99 cent bargains with inflated shipping, all they need to do is to continue buying from these sellers. But just wait until the honest sellers who can't compete leave, and see what happens to those bargain prices.

As long as so many buyers use the theory of  I don't care what the shipping is, I look at the combined total, inflated shipping will continue. Computer parts, cell phones, and small electronics are definitely some of the worst categories for it.  Sadly I don't think most buyers realize or care, how it hurts the honest sellers.

So as a buyer, what can you do?  First & foremost don't buy from a seller with obviously inflated shippping costs.  You can also report the seller for fee avoidance.  Just be sure before reporting any auction that the seller is genuinely avoiding fees by charging a high shipping cost.

Example: A seller charging $10 to send a $2.00 DVD via Media mail is very likely avoiding fees.  Another seller may be shipping a $2.00 item that weights several pounds & via Priority mail & is not avoiding fees by charging $10.00 shipping & handling for a $2.00 item. 

Cost of the item has no bearing on acutual shipping cost (except for increased costs for any insurance that may be added).  
A $1.00 may very well in reality cost more to package & ship than a $100 item.

Plus, please don't forget, charging a small handling fee in addition to actual postage is not fee avoidance.  Sellers do incur many additional expenses in the shipping process that they do need to be reimbursed for.  Everything from packing tape, bubble wrap, tissue paper, & padded envelopes to gas to get to the post office are legitimate costs.  I have seen buyers complain that when they recieved their package, shipping cost was less than charged.  Just because the postage on your package shows $5.00, doesn't mean that it may not have cost the seller a bit more to actually safely package & ship your item. 

Hopefully this guide may help to answer some questions regarding shipping costs, especially for new buyers.
If anyone - buyers or sellers - have any suggestions or comments regarding this guide, your input is most welcome!