From the 1980s to 2000s, the Sony Walkman and its many imitators were a very popular way to listen to cassette tapes on a pocket-sized player. A multitude of different brands and models were sold over the years, with quality and features ranging from cheap and basic to almost as good as a high-end component tape deck. Unfortunately, decent-quality, fully-working used ones are increasingly scarce and expensive, with highly sought-after Walkman models frequently selling for US$300 or more. All too often they are broken due to being dropped or having leaky batteries left in them, so if you are looking for a used Walkman-style player, shop carefully to avoid these problems.
Many inexpensive new Walkman-style cassette players and recorders sold today are low-quality monaural units designed for voice dictation, not music, and are best avoided. They suffer from poor audio quality, unstable speed, and problems playing tapes due to their cheap, inferior motors and mechanisms. However, some new Walkman-style cassette recorders sold today actually do play in stereo and have acceptable (but not great) audio quality and performance, such as the We Are Rewind WE-001 (US$149) and Mulann B-1000 (US$59):
For a beginner or casual use, many boomboxes and bookshelf stereo systems from the 1990s and 2000s contain cassette players and recorders which can deliver decent audio quality, and these are extremely plentiful and cheap in thrift stores, yard sales, online classified ads, etc.
For example, in 2019 I found a Sony CMT-NEZ30 micro bookshelf CD/cassette stereo system for $24.99 at Goodwill, one of the last of its kind from 2006, in perfect working condition, including speakers. And even a 1990s Soundesign stereo system is also capable of delivering surprisingly good cassette tape recording and playback quality:
Or if you want something new, the Sony CFD-S70 boombox (US$68) contains a good-quality cassette mechanism, although its speakers are a bit tinny-sounding. The Sony CFD-S401 (around US$135 on eBay, imported from Japan) and Panasonic RX-D55 (US$169) have larger, better-sounding speakers and more features.
But please avoid most of the new "retro-style" cassette boomboxes, as they usually are more about looks than sound quality, as shown in The 8-Bit Guy's review of a QFX "X-Bass" boombox, and Techmoan's review of the GPO Brooklyn:
One exception are the new cassette boomboxes by AudioCrazy, which play in stereo and have an improved tape mechanism and motor for much better speed stability, although the tiny built-in speakers sound shrill and the cassette recording quality is poor:
The new Marantz PMD-300CP (US$159) and Pyle PT-649D (US$169) cassette decks offer basic features at an affordable price, plus (on the Marantz) the ability to easily connect to your computer via USB and convert your tapes into digital audio files. There is no Dolby noise reduction (or equivalent) and these decks have several design quirks that may prove to be irritating, but the quality of the mechanisms and motors is adequate, thanks to improved components they began using in 2021.
If your budget allows, TEAC and TASCAM cassette decks and CD/cassette combo decks are the highest-quality ones made today. These have list prices of US$499 or more, but lately Onkyo has been selling refurbished TEAC W-1200s on their eBay store for $399.
Here's my detailed review and test of the TASCAM 202mkVII and TEAC W-1200 cassette decks, which are largely similar except for the minor differences explained in the video about the W-1200:
And here's my review of the TASCAM CD-A580 CD/cassette combo deck, also sold as the TEAC AD-850 (again with minor differences explained in the video):
Cassette decks from the 1980s, 1990s, and early 2000s from well-known brands like Sony, Pioneer, Technics, Kenwood, Onkyo, Yamaha, JVC, etc. almost always offer better audio quality, superior durability, and more features (such as Dolby Noise Reduction and the ability to record onto Type IV Metal tape) than modern entry-level decks, and will greatly outperform most portable cassette players and recorders.
This video is a beginners' guide to cassette decks, going over which features to look for, and how to test, clean, connect, and use them:
This video by Interface shows the basics of age-related maintenance that you may need to do on vintage cassette decks, such as cleaning, aligning, and demagnetizing the heads:
You may also need to eventually replace the belts in a vintage cassette deck, which is often rather tricky to do, and unfortunately it is impossible to offer a one-size-fits-all tutorial on how to replace the belts, due to the multitude of different designs of mechanisms used over the years. You may be able to find a tutorial specific to your make and model of deck, and a vendor selling a belt kit with exact replacements of the belts you'll need. Or you can avoid the problem by choosing a deck whose seller can assure you the belts were already replaced recently.
If you want to digitize your old tapes, you don't necessarily need a cassette player with USB output -- you can connect any cassette deck, boombox, Walkman, or bookshelf stereo system to your computer using a USB audio capture device costing around US$15 to $20. Just be sure to disable any bass boost, loudness, or equalization settings your cassette player may have when transferring the audio. Or, you won't need a USB output if your computer has a line-level audio input or a software-defined audio jack that can be set to Line In mode. This includes many older Macs, and most desktop PCs.
There are many online tutorials on transferring (sometimes incorrectly referred to as "ripping") analog audio into your computer, as well as free software like Audacity or Ocenaudio for recording and editing audio on your computer and saving it into your desired format (MP3, AAC, WAV, FLAC, etc.).