$150 might be a lot or a little, but keep in mind that depends on the dose. $150 might be a lot for a 4 week supply, but little for a 40 week supply.
Liquid clen is not better or worse by any means. One type of clen is not better than another. Clen is clen. Certainly, liquid clen might be slightly overdosed at times, but that doesn't mean it's stronger. It merely means that you're taking a higher dose. If that's a big deal to you, then you simply have to take more of the solid version (20-40mcg more).
Aspirin is aspirin, testosterone is testosterone, and clenbuterol is clenbuterol. 1mcg of liquid clenbuterol has the same strength as 1mcg of solid clenbuterol.