I just drove up to my local hobby (actually model airplane, boat, railroad) shop and it is no longer in business! It was there less than a month ago but has since disappeared. The reason I went to the shop was to purchase some brass strip 3/16ths inches wide for making the strip line tuned circuits for a 432 MHz preamplifier. But, since the store is no longer in business I had to look elsewhere for some material.
On a "hunch", I stopped by a Michael's store (this is a chain of hobby shops in the south) and "discovered" copper sheets that are several "mils" thick and can be cut with common scissors. The sheets are 9.25 inches by 12 inches and the cost was $5.99. Considering that the brass strips were usually $1.29 and were about 9 inches long the copper sheet was definitely a bargain.
The copper is sold for embossing projects and is 100 percent copper (and is a "product of the U.S.A.). The thickness is sufficient for receiving strip lines and for lower powered transmitting strip lines (I would guess up to 100 watts, maybe even more). What I bought was the AMACO brand part number 50066R and, again, the price was $5.99 for the sheet. It comes in a plastic tube about 2 inches in diameter.
Although I did not go across the street to the Hobby Lobby store, I would think that they would handle either the exact product or a similar product. Since metal embossing is fairly popular I expect that most general hobby stores would have similar copper sheets.
Glen, K9STH
Website: http://k9sth.com