Does anyone know what this symbol means?

Does it come from writing cheques/checks, where you fill the box with the number amount in with a line so no one can add more numbers? Long shot I know.

I think 大 was written ta in the Wade-Giles. craneboywill may be craneoldmanwill. Peita was what Beijing University used to be called, and I think that was an abbreviation for a long name that involved. 大.

All to be taken with a grain of salt; I don't know Chinese (although I knew 大 and 中 -- noddy badge for me!).

That's true, in Wade-Giles it was "ta." It's still not 中, though.

The university is 北大 -- today the transcription is "bei da." It's short for 北京大学 (Bejing daxue = Beijing university).

It was 'ta' in Wade-Giles becuase technically the initial consonant is an unaspirated voiceless+ stop, but to English speakers this sounds close to 'd'. Pinyin 't' was t' (ie t apostrophe) in Wade-Giles.

$2/? to as high as $8/?

I'm puzzled by the slash (/). Was it in the original? Did it look like $2/中? Or $2中?

With the slash, it might even be a Q in lousy handwriting. $2-8 per Quarter.

The slash was in the original: $2/中

The handwriting is very neat.

In other parts of the document the slash was used instead of parenthesis: your brother/s instead of your brother(s).

I'm thinking that possibly it might mean approximately or around in light of #9 saying "In Mandarin, 中 is "zhong". It means such things as "center" and "middle,"

From the FOAK:
>A slash followed by a dash is used to denote the conclusion of currency. For example, on a check or a hand-written invoice, somebody may write $50/- to denote the end of the currency. This keeps anybody from adding further digits to the end of the number.

I've never heard of that, and in any case, it's not your symbol.

Any chance it was a badly written ± (plus-minus)?

The more I think about it, the more those slashes puzzle me. I don't think your writer is a native speaker of American English or else he/she is following some weird 19th Century conventions. Is the document modern or from some archive?

I think I would recognize it if it were a 19th century convention.