The tools and the learning are free. Challenges and people are what you can add.

Yes. Every lesson, podcast episode, exercise, quiz, final exam and certificate stays free. Plus and Premium add challenges, weekly extras and people on top; they never lock the tools or the courses.

Plus unlocks every lab challenge and drill, unlimited saved projects, the libraries, bigger simulations, AI help in the labs, and a weekly issue (lab tasks and a project of the week, also by e-mail). Premium includes all of that, plus a 1-hour 1:1 session with a mentor every two weeks (booked on the Mentoring page), a monthly seminar and invitations to in-person gatherings.

With bKash: send the amount shown at checkout, then enter the TrxID. Someone on our team checks it, usually within a few hours, and e-mails you. Nothing renews automatically; pay again to add more days. You can also use coins and a coupon, and when they cover the whole price there is no bKash step at all.

Coins are a reward you earn on the site (on the Earn coins page, the only place we will ever show ads). They pay only towards Plus or Premium, at the rate shown at checkout. They have no cash value, cannot be exchanged for money or sent to someone else, and are not refunded. If a payment you used them on is not approved or is refunded, the coins come back to your account.

Finish half the lessons of any one course, and at least 5 lessons in all, and your first month of Plus is free. It comes once per account and e-mail address, and lessons only count when you complete them on the site, after reading them and answering their quiz.

Yes, within the rules on the Payments and refunds page (linked at the bottom of every page). The bKash part of a payment is refunded to the number you paid from; coins and coupons are not cash and are not refunded, but coins come back to your account.