cheap lenses

before i ask my question, understand that i am a beginning enthusiast, and do not foresee ever to make any money of photography.

i found some really cheap, tempting lenses on amazon.com. i assume they are low quality, but i was wondering whether anyone here had any experience with them. here are the links:

a 500mm for $90

http://www.amazon.com/exec/obidos/tg/detail/-/B000NOUGPW/ref=ord_cart_shr?%5Fencoding=UTF8&m=A36DL6WLK2RE7O&v=glance

and a phoenix 1000mm for $120

http://www.amazon.com/exec/obidos/tg/detail/-/B000NNUUX6/ref=ord_cart_shr?%5Fencoding=UTF8&m=A36DL6WLK2RE7O&v=glance

here is my question, understanding that these are not competitors to professional lenses for ten times the price, but are these completely useless? would this be basically throwing my money away? i was thinking of these for birding, using a mid range tripod. i would like to decorate a webpage and possibly make 5-7 inch prints.

any enlightened opinion welcome, but i really hope to hear from someone who has used the above lenses.

all the best.

--
óskar