Long nails, any ideas?

[hamsterbasil]

So Basil is getting older now and is a lot less active than he used to be. about 2 weeks ago I noticed that he was getting very long nails so I took him to get them trimmed by the vets (I am too nervous to do it myself) but now they have grown back again and are really long. I am not sure what to do because I can't keep taking him to the vets as it costs money and is stressful for him. I have read online that you can use sandpaper but I am worried about that hurting his little feet. I have a sand bath in his cage but that obviously isn't doing the job. Any ideas anyone?
Thanks in advance.