From my many years of digging (and yes I am bragging.
) make sure you ask the record store owner/worker first if it's alright to use your portable record player in their store. Some of the record store owners allowed me to use my friend's Numark PT-01 (which is an excellent choice by the way) and some other owners didn't because of possibly ruining/scratching the records.
If you run into the latter situation, just sell it to them that it would be their best profitable interest to let you use the portable turntable in their store (and tell them how cautious you will be with their records). Tell them, without the turntable you will walk out of their store with only a couple of albums that you guessed they might sound good. If you are allowed to use the turntable, you will be able to listen to more records which leads to purchasing more records and that you will let others know online (MPC Forums) that their record shop is a goldmine for vinyl record collectors.
MBP 11,3 | Logic Pro X | Traktor Pro | MPC2000XL, 4000, 3000LE | MV8800, TR-707, TR-808 & TR-909 | HR-16B Modded | Yamaha SU700 | ASR-10 | x0xb0x x2 | Technics SL-1200 & SL-1200GLD | 4000+ records