Built many a 555 timer circuit back in the day! But in modern times, I can get an ATMega328p already attached to a PC board for $2.50 and load code on it to do whatever I want, including blink a red LED.
Can you actually get a genuine Atmel for that price? Bottom-rung Chinese Arduino clones sure, but you better order 10 of them because they will randomly stop working as you're tinkering with your circuit.