WASHINGTON, March 29— The American Telephone and Telegraph Company today announced ''a guaranteed price list'' that shows consumers how much they would pay to buy the telephone they now rent if they wait until next year to make a decision. It lists the standard rotary dial instrument for $19.95.
In a filing with the Federal Communications Commission, the telephone giant noted that customers of its local Bell System companies in 34 states already have the option of buying the telephones now in their homes.
After the Bell System is broken up on Jan. 1, the ownership of those phones will switch from the local companies to A.T.& T. But that change will not affect a consumer's right to purchase the telephone or to continue renting it, A.T.& T. said.
The company proposed to guarantee its price list for selling rental phones after the breakup for ''at least two years.'' The price list shows the maximum charge for a standard rotary phone will be $19.95; for a standard Touch-Tone phone, $41.95; for a Princess rotary phone, $39.95; for a Princess Touch-Tone, $49.95; for a Trimline rotary, $44.95, and for a Trimline Touch-Tone, $54.95.
The company also unveiled its price list for those consumers who want to continue leasing their phone after the breakup. That list shows the monthly rental fee for a standard rotary phone will be $1.50; for a standard Touch-Tone, $2.85; for a Princess rotary, $3.15; for a Princess Touch-Tone, $4.05; for a Trimline rotary, $3.45, and for a Trimline Touch-Tone, $4.60.
