Chatting with my sister today we were discussing the best things to spend money on during pregnancy, either for mum or baby...seeing as there are SO many things promoted to pregnant women.
So, if you've had something really useful share it here 
Mine are (currently 38 weeks)....
Pregnancy pilates class. £5 for 1.5hrs each week, feel amazing during and after...
Fruit flavoured heartburn tablets. £2 for 98. I have a strip of them in every bag, room, pocket, car....
Mindful hypnobirthing audiobook. Sends me to sleep every night guaranteed. Really good content and can listen when pottering around doing things. Audible subscription...
£7.99
Maternity swimming costume for £10 and council swimming pool membership £20 a month. Go at 11am most days and the whole pool is totally empty. Feel like a millionaire that has my own pool.