You should really get another female rat to live with her. Rats are pack animals, and can develop psychological disorders if they are alone too much. So unless you can be with your rat nearly all the time that it is awake, she's going to need company. Two rats aren't any harder to take care of than one, so that shouldn't be a problem. And price shouldn't really be an issue. I've seen fast food combo meals more expensive than the fancy rats at the local pet stores.
Anni she is so cute and tiny. Bless her. She looks to of been well handled also, some can be jumpy at 1st lol.
My last rat died 7 months ago. I bought her with her sister and her sister lived about 3 years, Hayles lived a further 3 years on her own and died at the age of 6 years old of very old age!. She was ok on her own but I only had her in the cage when I was out or in bed, mind you some days I could be out all day. She was a happy girl though. Theyare best in a group, Im getting 3 babie girls in a couple of weeks.
she should be ok with the new rat just make sure they are simular ages ive had my two rats toby and cody for 2 months and today i got a new rat (roobs) and they have got used 2 each other in a matter of hours. if u do introduce a new rat make sure u clean the cage throughly so there isnt much sent of jess and then the new rat wont feel as intimadated! good luck *N*I*X*Y*