Yes, both DrLambda and GAJIX offer a Free Trial.
Pricing for DrLambda Starts at $10.62/month whereas for GAJIX Starts at $8/month.
GAJIX offers several advantages, including Instant information access, Analyzes any subject, Generates subject summaries, Provides key concept explanations, Offers study questions and many more functionalities.
The cons of GAJIX may include a Limited free trial, No offline access, No mobile application, No multilingual support. and Subjective topic relevancy