All the major dealers are totally cleaned out of silver rounds/bars. I noticed that the Westminster Mint still shows good availability of bullion rounds/bars @ under $25 per ounce. They are a good size mint that produces a lot of the bullion that's normally available at the big retail dealers. I've never purchased from them so I can't personally vouch for their reliability -- not that that means anything -- do your own homework. Check them out if you are frustrated that you can't find any cheap bullion.
On silver eagles, APMEX pre-sold ~50,000 eagles for April 24 shipping and then loaded another ~60,000 for April 30 delivery. Currently they are down to ~8,900 coins plus 168 in "mint direct" 20-coin tubes left. They're selling the stuff before it even comes in.
APMEX just added another ~100,000 silver eagles to it supply of those to be delivered by April 30. That's 200,000+ that they've put up for sale before they can ship any of them. As an authorized purchaser from the mint, they get first shot at anything the mint rations to the public.